[Code of Federal Regulations]
[Title 29, Volume 6]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 29CFR1910.1051]

[Page 397-425]
 
                             TITLE 29--LABOR
 
CHAPTER XVII--OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT 
                                OF LABOR
 
PART 1910--OCCUPATIONAL SAFETY AND HEALTH STANDARDS (CONTINUED)--Table of Contents
 
                Subpart Z--Toxic and Hazardous Substances
 
Sec. 1910.1051  1,3-Butadiene.

    (a) Scope and application. (1) This section applies to all 
occupational exposures to 1,3-Butadiene (BD), Chemical Abstracts Service 
Registry No. 106-99-0, except as provided in paragraph (a)(2) of this 
section.
    (2)(i) Except for the recordkeeping provisions in paragraph (m)(1) 
of this section, this section does not apply to the processing, use, or 
handling of products containing BD or to other work operations and 
streams in which BD is present where objective data are reasonably 
relied upon that demonstrate the work operation or the product or the 
group of products or operations to which it belongs may not reasonably 
be foreseen to release BD in airborne concentrations at or above the 
action level or in excess of the STEL under the expected conditions of 
processing, use, or handling that will cause the greatest possible 
release or in any plausible accident.
    (ii) This section also does not apply to work operations, products 
or streams where the only exposure to BD is from liquid mixtures 
containing 0.1% or less of BD by volume or the vapors released from such 
liquids, unless objective data become available that

[[Page 398]]

show that airborne concentrations generated by such mixtures can exceed 
the action level or STEL under reasonably predictable conditions of 
processing, use or handling that will cause the greatest possible 
release.
    (iii) Except for labeling requirements and requirements for 
emergency response, this section does not apply to the storage, 
transportation, distribution or sale of BD or liquid mixtures in intact 
containers or in transportation pipelines sealed in such a manner as to 
fully contain BD vapors or liquid.
    (3) Where products or processes containing BD are exempted under 
paragraph (a)(2) of this section, the employer shall maintain records of 
the objective data supporting that exemption and the basis for the 
employer's reliance on the data, as provided in paragraph (m)(1) of this 
section.
    (b) Definitions: For the purpose of this section, the following 
definitions shall apply:
    Action level means a concentration of airborne BD of 0.5 ppm 
calculated as an eight (8)-hour time-weighted average.
    Assistant Secretary means the Assistant Secretary of Labor for 
Occupational Safety and Health, U.S. Department of Labor, or designee.
    Authorized person means any person specifically designated by the 
employer, whose duties require entrance into a regulated area, or a 
person entering such an area as a designated representative of employees 
to exercise the right to observe monitoring and measuring procedures 
under paragraph (d)(8) of this section, or a person designated under the 
Act or regulations issued under the Act to enter a regulated area.
    1,3-Butadiene means an organic compound with chemical formula 
CH2=CH-CH=CH2 that has a molecular weight of 
approximately 54.15 gm/mole.
    Business day means any Monday through Friday, except those days 
designated as federal, state, local or company specific holidays.
    Complete Blood Count (CBC) means laboratory tests performed on whole 
blood specimens and includes the following: White blood cell count 
(WBC), hematocrit (Hct), red blood cell count (RBC), hemoglobin (Hgb), 
differential count of white blood cells, red blood cell morphology, red 
blood cell indices, and platelet count.
    Day means any part of a calendar day.
    Director means the Director of the National Institute for 
Occupational Safety and Health (NIOSH), U.S. Department of Health and 
Human Services, or designee.
    Emergency situation means any occurrence such as, but not limited 
to, equipment failure, rupture of containers, or failure of control 
equipment that may or does result in an uncontrolled significant release 
of BD.
    Employee exposure means exposure of a worker to airborne 
concentrations of BD which would occur if the employee were not using 
respiratory protective equipment.
    Objective data means monitoring data, or mathematical modelling or 
calculations based on composition, chemical and physical properties of a 
material, stream or product.
    Permissible Exposure Limits, PELs means either the 8 hour Time 
Weighted Average (8-hr TWA) exposure or the Short-Term Exposure Limit 
(STEL).
    Physician or other licensed health care professional is an 
individual whose legally permitted scope of practice (i.e., license, 
registration, or certification) allows him or her to independently 
provide or be delegated the responsibility to provide one or more of the 
specific health care services required by paragraph (k) of this section.
    Regulated area means any area where airborne concentrations of BD 
exceed or can reasonably be expected to exceed the 8-hour time weighted 
average (8-hr TWA) exposure of 1 ppm or the short-term exposure limit 
(STEL) of 5 ppm for 15 minutes.
    This section means this 1,3-butadiene standard.
    (c) Permissible exposure limits (PELs)--(1) Time-weighted average 
(TWA) limit. The employer shall ensure that no employee is exposed to an 
airborne concentration of BD in excess of one (1) part BD per million 
parts of air (ppm) measured as an eight (8)-hour time-weighted average.
    (2) Short-term exposure limit (STEL). The employer shall ensure that 
no employee is exposed to an airborne concentration of BD in excess of 
five parts

[[Page 399]]

of BD per million parts of air (5 ppm) as determined over a sampling 
period of fifteen (15) minutes.
    (d) Exposure monitoring--(1) General. (i) Determinations of employee 
exposure shall be made from breathing zone air samples that are 
representative of the 8-hour TWA and 15-minute short-term exposures of 
each employee.
    (ii) Representative 8-hour TWA employee exposure shall be determined 
on the basis of one or more samples representing full-shift exposure for 
each shift and for each job classification in each work area.
    (iii) Representative 15-minute short-term employee exposures shall 
be determined on the basis of one or more samples representing 15-minute 
exposures associated with operations that are most likely to produce 
exposures above the STEL for each shift and for each job classification 
in each work area.
    (iv) Except for the initial monitoring required under paragraph 
(d)(2) of this section, where the employer can document that exposure 
levels are equivalent for similar operations on different work shifts, 
the employer need only determine representative employee exposure for 
that operation from the shift during which the highest exposure is 
expected.
    (2) Initial monitoring. (i) Each employer who has a workplace or 
work operation covered by this section, shall perform initial monitoring 
to determine accurately the airborne concentrations of BD to which 
employees may be exposed, or shall rely on objective data pursuant to 
paragraph (a)(2)(i) of this section to fulfill this requirement.
    (ii) Where the employer has monitored within two years prior to the 
effective date of this section and the monitoring satisfies all other 
requirements of this section, the employer may rely on such earlier 
monitoring results to satisfy the requirements of paragraph (d)(2)(i) of 
this section, provided that the conditions under which the initial 
monitoring was conducted have not changed in a manner that may result in 
new or additional exposures.
    (3) Periodic monitoring and its frequency. (i) If the initial 
monitoring required by paragraph (d)(2) of this section reveals employee 
exposure to be at or above the action level but at or below both the 8-
hour TWA limit and the STEL, the employer shall repeat the 
representative monitoring required by paragraph (d)(1) of this section 
every twelve months.
    (ii) If the initial monitoring required by paragraph (d)(2) of this 
section reveals employee exposure to be above the 8-hour TWA limit, the 
employer shall repeat the representative monitoring required by 
paragraph (d)(1)(ii) of this section at least every three months until 
the employer has collected two samples per quarter (each at least 7 days 
apart) within a two-year period, after which such monitoring must occur 
at least every six months.
    (iii) If the initial monitoring required by paragraph (d)(2) of this 
section reveals employee exposure to be above the STEL, the employer 
shall repeat the representative monitoring required by paragraph 
(d)(1)(iii) of this section at least every three months until the 
employer has collected two samples per quarter (each at least 7 days 
apart) within a two-year period, after which such monitoring must occur 
at least every six months.
    (iv) The employer may alter the monitoring schedule from every six 
months to annually for any required representative monitoring for which 
two consecutive measurements taken at least 7 days apart indicate that 
employee exposure has decreased to or below the 8-hour TWA, but is at or 
above the action level.
    (4) Termination of monitoring. (i) If the initial monitoring 
required by paragraph (d)(2) of this section reveals employee exposure 
to be below the action level and at or below the STEL, the employer may 
discontinue the monitoring for employees whose exposures are represented 
by the initial monitoring.
    (ii) If the periodic monitoring required by paragraph (d)(3) of this 
section reveals that employee exposures, as indicated by at least two 
consecutive measurements taken at least 7 days apart, are below the 
action level and at or below the STEL, the employer may discontinue the 
monitoring

[[Page 400]]

for those employees who are represented by such monitoring.
    (5) Additional monitoring. (i) The employer shall institute the 
exposure monitoring required under paragraph (d) of this section 
whenever there has been a change in the production, process, control 
equipment, personnel or work practices that may result in new or 
additional exposures to BD or when the employer has any reason to 
suspect that a change may result in new or additional exposures.
    (ii) Whenever spills, leaks, ruptures or other breakdowns occur that 
may lead to employee exposure above the 8-hr TWA limit or above the 
STEL, the employer shall monitor [using leak source, such as direct 
reading instruments, area or personal monitoring], after the cleanup of 
the spill or repair of the leak, rupture or other breakdown, to ensure 
that exposures have returned to the level that existed prior to the 
incident.
    (6) Accuracy of monitoring. Monitoring shall be accurate, at a 
confidence level of 95 percent, to within plus or minus 25 percent for 
airborne concentrations of BD at or above the 1 ppm TWA limit and to 
within plus or minus 35 percent for airborne concentrations of BD at or 
above the action level of 0.5 ppm and below the 1 ppm TWA limit.
    (7) Employee notification of monitoring results. (i) The employer 
shall, within 5 business days after the receipt of the results of any 
monitoring performed under this section, notify the affected employees 
of these results in writing either individually or by posting of results 
in an appropriate location that is accessible to affected employees.
    (ii) The employer shall, within 15 business days after receipt of 
any monitoring performed under this section indicating the 8-hour TWA or 
STEL has been exceeded, provide the affected employees, in writing, with 
information on the corrective action being taken by the employer to 
reduce employee exposure to or below the 8-hour TWA or STEL and the 
schedule for completion of this action.
    (8) Observation of monitoring--(i) Employee observation. The 
employer shall provide affected employees or their designated 
representatives an opportunity to observe any monitoring of employee 
exposure to BD conducted in accordance with paragraph (d) of this 
section.
    (ii) Observation procedures. When observation of the monitoring of 
employee exposure to BD requires entry into an area where the use of 
protective clothing or equipment is required, the employer shall provide 
the observer at no cost with protective clothing and equipment, and 
shall ensure that the observer uses this equipment and complies with all 
other applicable safety and health procedures.
    (e) Regulated areas. (1) The employer shall establish a regulated 
area wherever occupational exposures to airborne concentrations of BD 
exceed or can reasonably be expected to exceed the permissible exposure 
limits, either the 8-hr TWA or the STEL.
    (2) Access to regulated areas shall be limited to authorized 
persons.
    (3) Regulated areas shall be demarcated from the rest of the 
workplace in any manner that minimizes the number of employees exposed 
to BD within the regulated area.
    (4) An employer at a multi-employer worksite who establishes a 
regulated area shall communicate the access restrictions and locations 
of these areas to other employers with work operations at that worksite 
whose employees may have access to these areas.
    (f) Methods of compliance--(1) Engineering controls and work 
practices. (i) The employer shall institute engineering controls and 
work practices to reduce and maintain employee exposure to or below the 
PELs, except to the extent that the employer can establish that these 
controls are not feasible or where paragraph (h)(1)(i) of this section 
applies.
    (ii) Wherever the feasible engineering controls and work practices 
which can be instituted are not sufficient to reduce employee exposure 
to or below the 8-hour TWA or STEL, the employer shall use them to 
reduce employee exposure to the lowest levels achievable by these 
controls and shall supplement them by the use of respiratory protection 
that complies with the requirements of paragraph (h) of this section.
    (2) Compliance plan. (i) Where any exposures are over the PELs, the 
employer shall establish and implement a

[[Page 401]]

written plan to reduce employee exposure to or below the PELs primarily 
by means of engineering and work practice controls, as required by 
paragraph (f)(1) of this section, and by the use of respiratory 
protection where required or permitted under this section. No compliance 
plan is required if all exposures are under the PELs.
    (ii) The written compliance plan shall include a schedule for the 
development and implementation of the engineering controls and work 
practice controls including periodic leak detection surveys.
    (iii) Copies of the compliance plan required in paragraph (f)(2) of 
this section shall be furnished upon request for examination and copying 
to the Assistant Secretary, the Director, affected employees and 
designated employee representatives. Such plans shall be reviewed at 
least every 12 months, and shall be updated as necessary to reflect 
significant changes in the status of the employer's compliance program.
    (iv) The employer shall not implement a schedule of employee 
rotation as a means of compliance with the PELs.
    (g) Exposure Goal Program. (1) For those operations and job 
classifications where employee exposures are greater than the action 
level, in addition to compliance with the PELs, the employer shall have 
an exposure goal program that is intended to limit employee exposures to 
below the action level during normal operations.
    (2) Written plans for the exposure goal program shall be furnished 
upon request for examination and copying to the Assistant Secretary, the 
Director, affected employees and designated employee representatives.
    (3) Such plans shall be updated as necessary to reflect significant 
changes in the status of the exposure goal program.
    (4) Respirator use is not required in the exposure goal program.
    (5) The exposure goal program shall include the following items 
unless the employer can demonstrate that the item is not feasible, will 
have no significant effect in reducing employee exposures, or is not 
necessary to achieve exposures below the action level:
    (i) A leak prevention, detection, and repair program.
    (ii) A program for maintaining the effectiveness of local exhaust 
ventilation systems.
    (iii) The use of pump exposure control technology such as, but not 
limited to, mechanical double-sealed or seal-less pumps.
    (iv) Gauging devices designed to limit employee exposure, such as 
magnetic gauges on rail cars.
    (v) Unloading devices designed to limit employee exposure, such as a 
vapor return system.
    (vi) A program to maintain BD concentration below the action level 
in control rooms by use of engineering controls.
    (h) Respiratory protection--(1) General. For employees who use 
respirators required by this section, the employer must provide 
respirators that comply with the requirements of this paragraph. 
Respirators must be used during:
    (i) Periods necessary to install or implement feasible engineering 
and work-practice controls.
    (ii) Non-routine work operations that are performed infrequently and 
for which employee exposures are limited in duration.
    (iii) Work operations for which feasible engineering and work-
practice controls are not yet sufficient to reduce employee exposures to 
or below the PELs.
    (iv) Emergencies.
    (2) Respirator program. (i) The employer must implement a 
respiratory protection program in accordance with 29 CFR 1910.134 (b) 
through (d) (except (d)(1)(iii), (d)(3)(iii)(B)(1), and (2)), and (f) 
through (m).
    (ii) If air-purifying respirators are used, the employer must 
replace the air-purifying filter elements according to the replacement 
schedule set for the class of respirators listed in Table 1 of this 
section, and at the beginning of each work shift.
    (iii) Instead of using the replacement schedule listed in Table 1 of 
this section, the employer may replace cartridges or canisters at 90% of 
their expiration service life, provided the employer:

[[Page 402]]

    (A) Demonstrates that employees will be adequately protected by this 
procedure.
    (B) Uses BD breakthrough data for this purpose that have been 
derived from tests conducted under worst-case conditions of humidity, 
temperature, and air-flow rate through the filter element, and the 
employer also describes the data supporting the cartridge-or canister-
change schedule, as well as the basis for using the data in the 
employer's respirator program.
    (iv) A label must be attached to each filter element to indicate the 
date and time it is first installed on the respirator.
    (v) If NIOSH approves an end-of-service-life indicator (ESLI) for an 
air-purifying filter element, the element may be used until the ESLI 
shows no further useful service life or until the element is replaced at 
the beginning of the next work shift, whichever occurs first.
    (vi) Regardless of the air-purifying element used, if an employee 
detects the odor of BD, the employer must replace the air-purifying 
element immediately.
    (3) Respirator selection. (i) The employer must select appropriate 
respirators from Table 1 of this section.

Table 1--Minimum Requirements for Respiratory Protection for Airborne BD
------------------------------------------------------------------------
 Concentration of airborne BD
  (ppm) or condition of use           Minimum required respirator
------------------------------------------------------------------------
Less than or equal to 5 ppm    (a) Air-purifying half mask or full
 (5 times PEL).                 facepiece respirator equipped with
                                approved BD or organic vapor cartridges
                                or canisters. Cartridges or canisters
                                shall be replaced every 4 hours.
Less than or equal to 10 ppm   (a) Air-purifying half mask or full
 (10 times PEL).                facepiece respirator equipped with
                                approved BD or organic vapor cartridges
                                or canisters. Cartridges or canisters
                                shall be replaced every 3 hours.
Less than or equal to 25 ppm   (a) Air-purifying full facepiece
 (25 times PEL).                respirator equipped with approved BD or
                                organic vapor cartridges or canisters.
                                Cartridges or canisters shall be
                                replaced every 2 hours.
                               (b) Any powered air-purifying respirator
                                equipped with approved BD or organic
                                vapor cartridges. PAPR cartridges shall
                                be replaced every 2 hours.
                               (c) Continuous flow supplied air
                                respirator equipped with a hood or
                                helmet.
Less than or equal to 50 ppm   (a) Air-purifying full facepiece
 (50 times PEL).                respirator equipped with approved BD or
                                organic vapor cartridges or canisters.
                                Cartridges or canisters shall be
                                replaced every (1) hour.
                               (b) Powered air-purifying respirator
                                equipped with a tight-fitting facepiece
                                and an approved BD or organic vapor
                                cartridges. PAPR cartridges shall be
                                replaced every (1) hour.
Less than or equal to 1,000    (a) Supplied air respirator equipped with
 ppm (1,000 times PEL).         a half mask of full facepiece and
                                operated in a pressure demand or other
                                positive pressure mode.
Greater than 1000 ppm unknown  (a) Self-contained breathing apparatus
 concentration, or              equipped with a full facepiece and
 firefighting.                  operated in a pressure demand or other
                                positive pressure mode.
                               (b) Any supplied air respirator equipped
                                with a full facepiece and operated in a
                                pressure demand or other positive
                                pressure mode in combination with an
                                auxiliary self-contained breathing
                                apparatus operated in a pressure demand
                                or other positive pressure mode.
Escape from IDLH conditions..  (a) Any positive pressure self-contained
                                breathing apparatus with an appropriate
                                service life.
                               (b) A air-purifying full facepiece
                                respirator equipped with a front or back
                                mounted BD or organic vapor canister.
------------------------------------------------------------------------
Notes: Respirators approved for use in higher concentrations are
  permitted to be used in lower concentrations. Full facepiece is
  required when eye irritation is anticipated.

    (ii) Air-purifying respirators must have filter elements approved by 
NIOSH for organic vapors or BD.
    (iii) When an employee whose job requires the use of a respirator 
cannot use a negative-pressure respirator, the employer must provide the 
employee with a respirator that has less breathing resistance than the 
negative-pressure respirator, such as a powered air-purifying respirator 
or supplied-air respirator, when the employee is able to use it and if 
it provides the employee adequate protection.
    (i) Protective clothing and equipment. Where appropriate to prevent 
eye contact and limit dermal exposure to BD, the employer shall provide 
protective clothing and equipment at no cost to the employee and shall 
ensure its use.

[[Page 403]]

Eye and face protection shall meet the requirements of 29 CFR 1910.133.
    (j) Emergency situations. Written plan. A written plan for emergency 
situations shall be developed, or an existing plan shall be modified, to 
contain the applicable elements specified in 29 CFR 1910.38 and 29 CFR 
1910.39, ``Emergency action plans'' and ``Fire prevention plans,'' 
respectively, and in 29 CFR 1910.120, ``Hazardous Waste Operations and 
Emergency Response,'' for each workplace where there is the possibility 
of an emergency.
    (k) Medical screening and surveillance--(1) Employees covered. The 
employer shall institute a medical screening and surveillance program as 
specified in this paragraph for:
    (i) Each employee with exposure to BD at concentrations at or above 
the action level on 30 or more days or for employees who have or may 
have exposure to BD at or above the PELs on 10 or more days a year;
    (ii) Employers (including successor owners) shall continue to 
provide medical screening and surveillance for employees, even after 
transfer to a non-BD exposed job and regardless of when the employee is 
transferred, whose work histories suggest exposure to BD:
    (A) At or above the PELs on 30 or more days a year for 10 or more 
years;
    (B) At or above the action level on 60 or more days a year for 10 or 
more years; or
    (C) Above 10 ppm on 30 or more days in any past year; and
    (iii) Each employee exposed to BD following an emergency situation.
    (2) Program administration. (i) The employer shall ensure that the 
health questionnaire, physical examination and medical procedures are 
provided without cost to the employee, without loss of pay, and at a 
reasonable time and place.
    (ii) Physical examinations, health questionnaires, and medical 
procedures shall be performed or administered by a physician or other 
licensed health care professional.
    (iii) Laboratory tests shall be conducted by an accredited 
laboratory.
    (3) Frequency of medical screening activities. The employer shall 
make medical screening available on the following schedule:
    (i) For each employee covered under paragraphs (j)(1) (i)-(ii) of 
this section, a health questionnaire and complete blood count with 
differential and platelet count (CBC) every year, and a physical 
examination as specified below:
    (A) An initial physical examination that meets the requirements of 
this rule, if twelve months or more have elapsed since the last physical 
examination conducted as part of a medical screening program for BD 
exposure;
    (B) Before assumption of duties by the employee in a job with BD 
exposure;
    (C) Every 3 years after the initial physical examination;
    (D) At the discretion of the physician or other licensed health care 
professional reviewing the annual health questionnaire and CBC;
    (E) At the time of employee reassignment to an area where exposure 
to BD is below the action level, if the employee's past exposure history 
does not meet the criteria of paragraph (j)(1)(ii) of this section for 
continued coverage in the screening and surveillance program, and if 
twelve months or more have elapsed since the last physical examination; 
and
    (F) At termination of employment if twelve months or more have 
elapsed since the last physical examination.
    (ii) Following an emergency situation, medical screening shall be 
conducted as quickly as possible, but not later than 48 hours after the 
exposure.
    (iii) For each employee who must wear a respirator, physical ability 
to perform the work and use the respirator must be determined as 
required by 29 CFR 1910.134.
    (4) Content of medical screening. (i) Medical screening for 
employees covered by paragraphs (j)(1) (i)-(ii) of this section shall 
include:
    (A) A baseline health questionnaire that includes a comprehensive 
occupational and health history and is updated annually. Particular 
emphasis shall be placed on the hematopoietic and reticuloendothelial 
systems, including exposure to chemicals, in addition to BD, that may 
have an adverse effect on these systems, the presence of signs and 
symptoms that might be related to disorders of these systems, and any 
other information determined by

[[Page 404]]

the examining physician or other licensed health care professional to be 
necessary to evaluate whether the employee is at increased risk of 
material impairment of health from BD exposure. Health questionnaires 
shall consist of the sample forms in Appendix C to this section, or be 
equivalent to those samples;
    (B) A complete physical examination, with special emphasis on the 
liver, spleen, lymph nodes, and skin;
    (C) A CBC; and
    (D) Any other test which the examining physician or other licensed 
health care professional deems necessary to evaluate whether the 
employee may be at increased risk from exposure to BD.
    (ii) Medical screening for employees exposed to BD in an emergency 
situation shall focus on the acute effects of BD exposure and at a 
minimum include: A CBC within 48 hours of the exposure and then monthly 
for three months; and a physical examination if the employee reports 
irritation of the eyes, nose throat, lungs, or skin, blurred vision, 
coughing, drowsiness, nausea, or headache. Continued employee 
participation in the medical screening and surveillance program, beyond 
these minimum requirements, shall be at the discretion of the physician 
or other licensed health care professional.
    (5) Additional medical evaluations and referrals. (i) Where the 
results of medical screening indicate abnormalities of the hematopoietic 
or reticuloendothelial systems, for which a non-occupational cause is 
not readily apparent, the examining physician or other licensed health 
care professional shall refer the employee to an appropriate specialist 
for further evaluation and shall make available to the specialist the 
results of the medical screening.
    (ii) The specialist to whom the employee is referred under this 
paragraph shall determine the appropriate content for the medical 
evaluation, e.g., examinations, diagnostic tests and procedures, etc.
    (6) Information provided to the physician or other licensed health 
care professional. The employer shall provide the following information 
to the examining physician or other licensed health care professional 
involved in the evaluation:
    (i) A copy of this section including its appendices;
    (ii) A description of the affected employee's duties as they relate 
to the employee's BD exposure;
    (iii) The employee's actual or representative BD exposure level 
during employment tenure, including exposure incurred in an emergency 
situation;
    (iv) A description of pertinent personal protective equipment used 
or to be used; and
    (v) Information, when available, from previous employment-related 
medical evaluations of the affected employee which is not otherwise 
available to the physician or other licensed health care professional or 
the specialist.
    (7) The written medical opinion. (i) For each medical evaluation 
required by this section, the employer shall ensure that the physician 
or other licensed health care professional produces a written opinion 
and provides a copy to the employer and the employee within 15 business 
days of the evaluation. The written opinion shall be limited to the 
following information:
    (A) The occupationally pertinent results of the medical evaluation;
    (B) A medical opinion concerning whether the employee has any 
detected medical conditions which would place the employee's health at 
increased risk of material impairment from exposure to BD;
    (C) Any recommended limitations upon the employee's exposure to BD; 
and
    (D) A statement that the employee has been informed of the results 
of the medical evaluation and any medical conditions resulting from BD 
exposure that require further explanation or treatment.
    (ii) The written medical opinion provided to the employer shall not 
reveal specific records, findings, and diagnoses that have no bearing on 
the employee's ability to work with BD.
    Note: However, this provision does not negate the ethical obligation 
of the physician or other licensed health care professional to transmit 
any other adverse findings directly to the employee.

[[Page 405]]

    (8) Medical surveillance. (i) The employer shall ensure that 
information obtained from the medical screening program activities is 
aggregated (with all personal identifiers removed) and periodically 
reviewed, to ascertain whether the health of the employee population of 
that employer is adversely affected by exposure to BD.
    (ii) Information learned from medical surveillance activities must 
be disseminated to covered employees, as defined in paragraph (k)(1) of 
this section, in a manner that ensures the confidentiality of individual 
medical information.
    (l) Communication of BD hazards to employees--(1) Hazard 
communication. The employer shall communicate the hazards associated 
with BD exposure in accordance with the requirements of the Hazard 
Communication Standard, 29 CFR 1910.1200, 29 CFR 1915.1200, and 29 CFR 
1926.59.
    (2) Employee information and training. (i) The employer shall 
provide all employees exposed to BD with information and training in 
accordance with the requirements of the Hazard Communication Standard, 
29 CFR 1910.1200, 29 CFR 1915.1200, and 29 CFR 1926.59.
    (ii) The employer shall institute a training program for all 
employees who are potentially exposed to BD at or above the action level 
or the STEL, ensure employee participation in the program and maintain a 
record of the contents of such program.
    (iii) Training shall be provided prior to or at the time of initial 
assignment to a job potentially involving exposure to BD at or above the 
action level or STEL and at least annually thereafter.
    (iv) The training program shall be conducted in a manner that the 
employee is able to understand. The employee shall ensure that each 
employee exposed to BD over the action level or STEL is informed of the 
following:
    (A) The health hazards associated with BD exposure, and the purpose 
and a description of the medical screening and surveillance program 
required by this section;
    (B) The quantity, location, manner of use, release, and storage of 
BD and the specific operations that could result in exposure to BD, 
especially exposures above the PEL or STEL;
    (C) The engineering controls and work practices associated with the 
employee's job assignment, and emergency procedures and personal 
protective equipment;
    (D) The measures employees can take to protect themselves from 
exposure to BD.
    (E) The contents of this standard and its appendices, and
    (F) The right of each employee exposed to BD at or above the action 
level or STEL to obtain:
    (1) medical examinations as required by paragraph (j) of this 
section at no cost to the employee;
    (2) the employee's medical records required to be maintained by 
paragraph (m)(4) of this section; and
    (3) all air monitoring results representing the employee's exposure 
to BD and required to be kept by paragraph (m)(2) of this section.
    (3) Access to information and training materials. (i) The employer 
shall make a copy of this standard and its appendices readily available 
without cost to all affected employees and their designated 
representatives and shall provide a copy if requested.
    (ii) The employer shall provide to the Assistant Secretary or the 
Director, or the designated employee representatives, upon request, all 
materials relating to the employee information and the training program.
    (m) Recordkeeping--(1) Objective data for exemption from initial 
monitoring. (i) Where the processing, use, or handling of products or 
streams made from or containing BD are exempted from other requirements 
of this section under paragraph (a)(2) of this section, or where 
objective data have been relied on in lieu of initial monitoring under 
paragraph (d)(2)(ii) of this section, the employer shall establish and 
maintain a record of the objective data reasonably relied upon in 
support of the exemption.
    (ii) This record shall include at least the following information:
    (A) The product or activity qualifying for exemption;
    (B) The source of the objective data;
    (C) The testing protocol, results of testing, and analysis of the 
material for the release of BD;

[[Page 406]]

    (D) A description of the operation exempted and how the data support 
the exemption; and
    (E) Other data relevant to the operations, materials, processing, or 
employee exposures covered by the exemption.
    (iii) The employer shall maintain this record for the duration of 
the employer's reliance upon such objective data.
    (2) Exposure measurements. (i) The employer shall establish and 
maintain an accurate record of all measurements taken to monitor 
employee exposure to BD as prescribed in paragraph (d) of this section.
    (ii) The record shall include at least the following information:
    (A) The date of measurement;
    (B) The operation involving exposure to BD which is being monitored;
    (C) Sampling and analytical methods used and evidence of their 
accuracy;
    (D) Number, duration, and results of samples taken;
    (E) Type of protective devices worn, if any; and
    (F) Name, social security number and exposure of the employees whose 
exposures are represented.
    (G) The written corrective action and the schedule for completion of 
this action required by paragraph (d)(7)(ii) of this section.
    (iii) The employer shall maintain this record for at least 30 years 
in accordance with 29 CFR 1910.20.
    (3) Respirator Fit-test. (i) The employer shall establish a record 
of the fit tests administered to an employee including:
    (A) The name of the employee,
    (B) Type of respirator,
    (C) Brand and size of respirator,
    (D) Date of test, and
    (E) Where QNFT is used, the fit factor, strip chart recording or 
other recording of the results of the test.
    (ii) Fit test records shall be maintained for respirator users until 
the next fit test is administered.
    (4) Medical screening and surveillance. (i) The employer shall 
establish and maintain an accurate record for each employee subject to 
medical screening and surveillance under this section.
    (ii) The record shall include at least the following information:
    (A) The name and social security number of the employee;
    (B) Physician's or other licensed health care professional's written 
opinions as described in paragraph (k)(7) of this section;
    (C) A copy of the information provided to the physician or other 
licensed health care professional as required by paragraphs (k)(7)(ii)-
(iv) of this section.
    (iii) Medical screening and surveillance records shall be maintained 
for each employee for the duration of employment plus 30 years, in 
accordance with 29 CFR 1910.20.
    (5) Availability. (i) The employer, upon written request, shall make 
all records required to be maintained by this section available for 
examination and copying to the Assistant Secretary and the Director.
    (ii) Access to records required to be maintained by paragraphs 
(l)(1)-(3) of this section shall be granted in accordance with 29 CFR 
1910.20(e).
    (6) Transfer of records. (i) Whenever the employer ceases to do 
business, the employer shall transfer records required by this section 
to the successor employer. The successor employer shall receive and 
maintain these records. If there is no successor employer, the employer 
shall notify the Director, at least three (3) months prior to disposal, 
and transmit them to the Director if requested by the Director within 
that period.
    (ii) The employer shall transfer medical and exposure records as set 
forth in 29 CFR 1910.20(h).
    (n) Dates--(1) Effective date. This section shall become effective 
ninety (90) days after the date of publication in the Federal Register.
    (2) Start-up dates. (i) The initial monitoring required under 
paragraph (d)(2) of this section shall be completed within sixty (60) 
days of the effective date of this standard or the introduction of BD 
into the workplace.
    (ii) The requirements of paragraphs (c) through (m) of this section, 
including feasible work practice controls but not including engineering 
controls specified in paragraph (f)(1) of this section, shall be 
complied with within one-hundred and eighty (180) days after the 
effective date of this section.

[[Page 407]]

    (iii) Engineering controls specified by paragraph (f)(1) of this 
section shall be implemented within two (2) years after the effective 
date of this section, and the exposure goal program specified in 
paragraph (g) of this section shall be implemented within three (3) 
years after the effective date of this section.
    (o) Appendices. (1) Appendix E to this section is mandatory.
    (2) Appendices A, B, C, D, and F to this section are informational 
and are not intended to create any additional obligations not otherwise 
imposed or to detract from any existing obligations.

   Appendix A to Sec. 1910.1051--Substance Safety Data Sheet For 1,3-
                        Butadiene (Non-Mandatory)

                       I. Substance Identification

    A. Substance: 1,3-Butadiene (CH2=CH-CH=CH2).
    B. Synonyms: 1,3-Butadiene (BD); butadiene; biethylene; bi-vinyl; 
divinyl; butadiene-1,3; buta-1,3-diene; erythrene; NCI-C50602; CAS-106-
99-0.
    C. BD can be found as a gas or liquid.
    D. BD is used in production of styrene-butadiene rubber and 
polybutadiene rubber for the tire industry. Other uses include copolymer 
latexes for carpet backing and paper coating, as well as resins and 
polymers for pipes and automobile and appliance parts. It is also used 
as an intermediate in the production of such chemicals as fungicides.
    E. Appearance and odor: BD is a colorless, non-corrosive, flammable 
gas with a mild aromatic odor at standard ambient temperature and 
pressure.
    F. Permissible exposure: Exposure may not exceed 1 part BD per 
million parts of air averaged over the 8-hour workday, nor may short-
term exposure exceed 5 parts of BD per million parts of air averaged 
over any 15-minute period in the 8-hour workday.

                         II. Health Hazard Data

    A. BD can affect the body if the gas is inhaled or if the liquid 
form, which is very cold (cryogenic), comes in contact with the eyes or 
skin.
    B. Effects of overexposure: Breathing very high levels of BD for a 
short time can cause central nervous system effects, blurred vision, 
nausea, fatigue, headache, decreased blood pressure and pulse rate, and 
unconsciousness. There are no recorded cases of accidental exposures at 
high levels that have caused death in humans, but this could occur. 
Breathing lower levels of BD may cause irritation of the eyes, nose, and 
throat. Skin contact with liquefied BD can cause irritation and 
frostbite.
    C. Long-term (chronic) exposure: BD has been found to be a potent 
carcinogen in rodents, inducing neoplastic lesions at multiple target 
sites in mice and rats. A recent study of BD-exposed workers showed that 
exposed workers have an increased risk of developing leukemia. The risk 
of leukemia increases with increased exposure to BD. OSHA has concluded 
that there is strong evidence that workplace exposure to BD poses an 
increased risk of death from cancers of the lymphohematopoietic system.
    D. Reporting signs and symptoms: You should inform your supervisor 
if you develop any of these signs or symptoms and suspect that they are 
caused by exposure to BD.

                   III. Emergency First Aid Procedures

    In the event of an emergency, follow the emergency plan and 
procedures designated for your work area. If you have been trained in 
first aid procedures, provide the necessary first aid measures. If 
necessary, call for additional assistance from co-workers and emergency 
medical personnel.
    A. Eye and Skin Exposures: If there is a potential that liquefied BD 
can come in contact with eye or skin, face shields and skin protective 
equipment must be provided and used. If liquefied BD comes in contact 
with the eye, immediately flush the eyes with large amounts of water, 
occasionally lifting the lower and the upper lids. Flush repeatedly. Get 
medical attention immediately. Contact lenses should not be worn when 
working with this chemical. In the event of skin contact, which can 
cause frostbite, remove any contaminated clothing and flush the affected 
area repeatedly with large amounts of tepid water.
    B. Breathing: If a person breathes in large amounts of BD, move the 
exposed person to fresh air at once. If breathing has stopped, begin 
cardiopulmonary resuscitation (CPR) if you have been trained in this 
procedure. Keep the affected person warm and at rest. Get medical 
attention immediately.
    C. Rescue: Move the affected person from the hazardous exposure. If 
the exposed person has been overcome, call for help and begin emergency 
rescue procedures. Use extreme caution so that you do not become a 
casualty. Understand the plant's emergency rescue procedures and know 
the locations of rescue equipment before the need arises.

                 IV. Respirators and Protective Clothing

    A. Respirators: Good industrial hygiene practices recommend that 
engineering and work practice controls be used to reduce environmental 
concentrations to the permissible exposure level. However, there are 
some exceptions where respirators may be used to control exposure. 
Respirators may be used when engineering and work practice controls

[[Page 408]]

are not technically feasible, when such controls are in the process of 
being installed, or when these controls fail and need to be supplemented 
or during brief, non-routine, intermittent exposure. Respirators may 
also be used in situations involving non-routine work operations which 
are performed infrequently and in which exposures are limited in 
duration, and in emergency situations. In some instances cartridge 
respirator use is allowed, but only with strict time constraints. For 
example, at exposure below 5 ppm BD, a cartridge (or canister) 
respirator, either full or half face, may be used, but the cartridge 
must be replaced at least every 4 hours, and it must be replaced every 3 
hours when the exposure is between 5 and 10 ppm. If the use of 
respirators is necessary, the only respirators permitted are those that 
have been approved by the National Institute for Occupational Safety and 
Health (NIOSH). In addition to respirator selection, a complete 
respiratory protection program must be instituted which includes regular 
training, maintenance, fit testing, inspection, cleaning, and evaluation 
of respirators. If you can smell BD while wearing a respirator, proceed 
immediately to fresh air, and change cartridge (or canister) before re-
entering an area where there is BD exposure. If you experience 
difficulty in breathing while wearing a respirator, tell your 
supervisor.
    B. Protective Clothing: Employees should be provided with and 
required to use impervious clothing, gloves, face shields (eight-inch 
minimum), and other appropriate protective clothing necessary to prevent 
the skin from becoming frozen by contact with liquefied BD (or a vessel 
containing liquid BD).
    Employees should be provided with and required to use splash-proof 
safety goggles where liquefied BD may contact the eyes.

           V. Precautions for Safe Use, Handling, and Storage

    A. Fire and Explosion Hazards: BD is a flammable gas and can easily 
form explosive mixtures in air. It has a lower explosive limit of 2%, 
and an upper explosive limit of 11.5%. It has an autoignition 
temperature of 420  deg.C (788  deg.F). Its vapor is heavier than air 
(vapor density, 1.9) and may travel a considerable distance to a source 
of ignition and flash back. Usually it contains inhibitors to prevent 
self-polymerization (which is accompanied by evolution of heat) and to 
prevent formation of explosive peroxides. At elevated temperatures, such 
as in fire conditions, polymerization may take place. If the 
polymerization takes place in a container, there is a possibility of 
violent rupture of the container.
    B. Hazard: Slightly toxic. Slight respiratory irritant. Direct 
contact of liquefied BD on skin may cause freeze burns and frostbite.
    C. Storage: Protect against physical damage to BD containers. 
Outside or detached storage of BD containers is preferred. Inside 
storage should be in a cool, dry, well-ventilated, noncombustible 
location, away from all possible sources of ignition. Store cylinders 
vertically and do not stack. Do not store with oxidizing material.
    D. Usual Shipping Containers: Liquefied BD is contained in steel 
pressure apparatus.
    E. Electrical Equipment: Electrical installations in Class I 
hazardous locations, as defined in Article 500 of the National 
Electrical Code, should be in accordance with Article 501 of the Code. 
If explosion-proof electrical equipment is necessary, it shall be 
suitable for use in Group B. Group D equipment may be used if such 
equipment is isolated in accordance with Section 501-5(a) by sealing all 
conduit \1/2\- inch size or larger. See Venting of Deflagrations (NFPA 
No. 68, 1994), National Electrical Code (NFPA No. 70, 1996 ), Static 
Electricity (NFPA No. 77, 1993), Lightning Protection Systems (NFPA No. 
780, 1995), and Fire Hazard Properties of Flammable Liquids, Gases and 
Volatile Solids (NFPA No. 325, 1994).
    F. Fire Fighting: Stop flow of gas. Use water to keep fire-exposed 
containers cool. Fire extinguishers and quick drenching facilities must 
be readily available, and you should know where they are and how to 
operate them.
    G. Spill and Leak: Persons not wearing protective equipment and 
clothing should be restricted from areas of spills or leaks until clean-
up has been completed. If BD is spilled or leaked, the following steps 
should be taken:
    1. Eliminate all ignition sources.
    2. Ventilate area of spill or leak.
    3. If in liquid form, for small quantities, allow to evaporate in a 
safe manner.
    4. Stop or control the leak if this can be done without risk. If 
source of leak is a cylinder and the leak cannot be stopped in place, 
remove the leaking cylinder to a safe place and repair the leak or allow 
the cylinder to empty.
    H. Disposal: This substance, when discarded or disposed of, is a 
hazardous waste according to Federal regulations (40 CFR part 261). It 
is listed as hazardous waste number D001 due to its ignitability. The 
transportation, storage, treatment, and disposal of this waste material 
must be conducted in compliance with 40 CFR parts 262, 263, 264, 268 and 
270. Disposal can occur only in properly permitted facilities. Check 
state and local regulation of any additional requirements as these may 
be more restrictive than federal laws and regulation.
    I. You should not keep food, beverages, or smoking materials in 
areas where there is BD exposure, nor should you eat or drink in such 
areas.

[[Page 409]]

    J. Ask your supervisor where BD is used in your work area and ask 
for any additional plant safety and health rules.

                        VI. Medical Requirements

    Your employer is required to offer you the opportunity to 
participate in a medical screening and surveillance program if you are 
exposed to BD at concentrations exceeding the action level (0.5 ppm BD 
as an 8-hour TWA) on 30 days or more a year, or at or above the 8 hr TWA 
(1 ppm) or STEL (5 ppm for 15 minutes) on 10 days or more a year. 
Exposure for any part of a day counts. If you have had exposure to BD in 
the past, but have been transferred to another job, you may still be 
eligible to participate in the medical screening and surveillance 
program. The OSHA rule specifies the past exposures that would qualify 
you for participation in the program. These past exposure are work 
histories that suggest the following: (1) That you have been exposed at 
or above the PELs on 30 days a year for 10 or more years; (2) that you 
have been exposed at or above the action level on 60 days a year for 10 
or more years; or (3) that you have been exposed above 10 ppm on 30 days 
in any past year. Additionally, if you are exposed to BD in an emergency 
situation, you are eligible for a medical examination within 48 hours. 
The basic medical screening program includes a health questionnaire, 
physical examination, and blood test. These medical evaluations must be 
offered to you at a reasonable time and place, and without cost or loss 
of pay.

                     VII. Observation of Monitoring

    Your employer is required to perform measurements that are 
representative of your exposure to BD and you or your designated 
representative are entitled to observe the monitoring procedure. You are 
entitled to observe the steps taken in the measurement procedure, and to 
record the results obtained. When the monitoring procedure is taking 
place in an area where respirators or personal protective clothing and 
equipment are required to be worn, you or your representative must also 
be provided with, and must wear, the protective clothing and equipment.

                       VIII. Access to Information

    A. Each year, your employer is required to inform you of the 
information contained in this appendix. In addition, your employer must 
instruct you in the proper work practices for using BD, emergency 
procedures, and the correct use of protective equipment.
    B. Your employer is required to determine whether you are being 
exposed to BD. You or your representative has the right to observe 
employee measurements and to record the results obtained. Your employer 
is required to inform you of your exposure. If your employer determines 
that you are being overexposed, he or she is required to inform you of 
the actions which are being taken to reduce your exposure to within 
permissible exposure limits and of the schedule to implement these 
actions.
    C. Your employer is required to keep records of your exposures and 
medical examinations. These records must be kept by the employer for at 
least thirty (30) years.
    D. Your employer is required to release your exposure and medical 
records to you or your representative upon your request.

  Appendix B to Sec. 1910.1051--Substance Technical Guidelines for 1,3-
                        Butadiene (Non-Mandatory)

                      I. Physical and Chemical Data

    A. Substance identification:
    1. Synonyms: 1,3-Butadiene (BD); butadiene; biethylene; bivinyl; 
divinyl; butadiene-1,3; buta-1,3-diene; erythrene; NCI-C50620; CAS-106-
99-0.
    2. Formula: CH2=CH-CH=CH2.
    3. Molecular weight: 54.1.
    B. Physical data:
    1. Boiling point (760 mm Hg): -4.7  deg.C (23.5  deg.F).
    2. Specific gravity (water=1): 0.62 at 20  deg.C (68  deg.F).
    3. Vapor density (air=1 at boiling point of BD): 1.87.
    4. Vapor pressure at 20  deg.C (68  deg.F): 910 mm Hg.
    5. Solubility in water, g/100 g water at 20  deg.C (68  deg.F): 
0.05.
    6. Appearance and odor: Colorless, flammable gas with a mildly 
aromatic odor. Liquefied BD is a colorless liquid with a mildly aromatic 
odor.

             II. Fire, Explosion, and Reactivity Hazard Data

    A. Fire:
    1. Flash point: -76  deg.C (-105  deg.F) for take out; liquefied BD; 
Not applicable to BD gas.
    2. Stability: A stabilizer is added to the monomer to inhibit 
formation of polymer during storage. Forms explosive peroxides in air in 
absence of inhibitor.
    3. Flammable limits in air, percent by volume: Lower: 2.0; Upper: 
11.5.
    4. Extinguishing media: Carbon dioxide for small fires, polymer or 
alcohol foams for large fires.
    5. Special fire fighting procedures: Fight fire from protected 
location or maximum possible distance. Stop flow of gas before 
extinguishing fire. Use water spray to keep fire-exposed cylinders cool.
    6. Unusual fire and explosion hazards: BD vapors are heavier than 
air and may travel to a source of ignition and flash back. Closed 
containers may rupture violently when heated.

[[Page 410]]

    7. For purposes of compliance with the requirements of 29 CFR 
1910.106, BD is classified as a flammable gas. For example, 7,500 ppm, 
approximately one-fourth of the lower flammable limit, would be 
considered to pose a potential fire and explosion hazard.
    8. For purposes of compliance with 29 CFR 1910.155, BD is classified 
as a Class B fire hazard.
    9. For purposes of compliance with 29 CFR 1910.307, locations 
classified as hazardous due to the presence of BD shall be Class I.
    B. Reactivity:
    1. Conditions contributing to instability: Heat. Peroxides are 
formed when inhibitor concentration is not maintained at proper level. 
At elevated temperatures, such as in fire conditions, polymerization may 
take place.
    2. Incompatibilities: Contact with strong oxidizing agents may cause 
fires and explosions. The contacting of crude BD (not BD monomer) with 
copper and copper alloys may cause formations of explosive copper 
compounds.
    3. Hazardous decomposition products: Toxic gases (such as carbon 
monoxide) may be released in a fire involving BD.
    4. Special precautions: BD will attack some forms of plastics, 
rubber, and coatings. BD in storage should be checked for proper 
inhibitor content, for self-polymerization, and for formation of 
peroxides when in contact with air and iron. Piping carrying BD may 
become plugged by formation of rubbery polymer.
    C. Warning Properties:
    1. Odor Threshold: An odor threshold of 0.45 ppm has been reported 
in The American Industrial Hygiene Association (AIHA) Report, Odor 
Thresholds for Chemicals with Established Occupational Health Standards. 
(Ex. 32-28C)
    2. Eye Irritation Level: Workers exposed to vapors of BD 
(concentration or purity unspecified) have complained of irritation of 
eyes, nasal passages, throat, and lungs. Dogs and rabbits exposed 
experimentally to as much as 6700 ppm for 7\1/2\ hours a day for 8 
months have developed no histologically demonstrable abnormality of the 
eyes.
    3. Evaluation of Warning Properties: Since the mean odor threshold 
is about half of the 1 ppm PEL, and more than 10-fold below the 5 ppm 
STEL, most wearers of air purifying respirators should still be able to 
detect breakthrough before a significant overexposure to BD occurs.

                III. Spill, Leak, and Disposal Procedures

    A. Persons not wearing protective equipment and clothing should be 
restricted from areas of spills or leaks until cleanup has been 
completed. If BD is spilled or leaked, the following steps should be 
taken:
    1. Eliminate all ignition sources.
    2. Ventilate areas of spill or leak.
    3. If in liquid form, for small quantities, allow to evaporate in a 
safe manner.
    4. Stop or control the leak if this can be done without risk. If 
source of leak is a cylinder and the leak cannot be stopped in place, 
remove the leaking cylinder to a safe place and repair the leak or allow 
the cylinder to empty.
    B. Disposal: This substance, when discarded or disposed of, is a 
hazardous waste according to Federal regulations (40 CFR part 261). It 
is listed by the EPA as hazardous waste number D001 due to its 
ignitability. The transportation, storage, treatment, and disposal of 
this waste material must be conducted in compliance with 40 CFR parts 
262, 263, 264, 268 and 270. Disposal can occur only in properly 
permitted facilities. Check state and local regulations for any 
additional requirements because these may be more restrictive than 
federal laws and regulations.

                IV. Monitoring and Measurement Procedures

    A. Exposure above the Permissible Exposure Limit (8-hr TWA) or 
Short-Term Exposure Limit (STEL):
    1. 8-hr TWA exposure evaluation: Measurements taken for the purpose 
of determining employee exposure under this standard are best taken with 
consecutive samples covering the full shift. Air samples must be taken 
in the employee's breathing zone (air that would most nearly represent 
that inhaled by the employee).
    2. STEL exposure evaluation: Measurements must represent 15 minute 
exposures associated with operations most likely to exceed the STEL in 
each job and on each shift.
    3. Monitoring frequencies: Table 1 gives various exposure scenarios 
and their required monitoring frequencies, as required by the final 
standard for occupational exposure to butadiene.

    Table 1--Five Exposure Scenarios and Their Associated Monitoring
                               Frequencies
------------------------------------------------------------------------
 Action    8-hr
  level     TWA    STEL            Required monitoring activity
------------------------------------------------------------------------
 -[ast]       -       -   No 8-hr TWA or STEL monitoring required.
 +[ast]       -       -   No STEL monitoring required. Monitor 8-hr TWA
                           annually.
      +       +       -   No STEL monitoring required. Periodic
                           monitoring 8-hr TWA, in accordance with
                           (d)(3)(ii).[ast][ast]
      +       +       +   Periodic monitoring 8-hr TWA, in accordance
                           with (d)(3)(ii)[ast][ast]. Periodic
                           monitoring STEL, in accordance with
                           (d)(3)(iii).
      +       -       +   Periodic monitoring STEL, in accordance with
                           (d)(3)(iii). Monitor 8-hr TWA, annually.
------------------------------------------------------------------------
[ast] Exposure Scenario, Limit Exceeded: + = Yes, -= No.

[[Page 411]]


[ast][ast] The employer may decrease the frequency of exposure
  monitoring to annually when at least 2 consecutive measurements taken
  at least 7 days apart show exposures to be below the 8 hr TWA, but at
  or above the action level.

    4. Monitoring techniques: Appendix D describes the validated method 
of sampling and analysis which has been tested by OSHA for use with BD. 
The employer has the obligation of selecting a monitoring method which 
meets the accuracy and precision requirements of the standard under his 
or her unique field conditions. The standard requires that the method of 
monitoring must be accurate, to a 95 percent confidence level, to plus 
or minus 25 percent for concentrations of BD at or above 1 ppm, and to 
plus or minus 35 percent for concentrations below 1 ppm.

                    V. Personal Protective Equipment

    A. Employees should be provided with and required to use impervious 
clothing, gloves, face shields (eight-inch minimum), and other 
appropriate protective clothing necessary to prevent the skin from 
becoming frozen from contact with liquid BD.
    B. Any clothing which becomes wet with liquid BD should be removed 
immediately and not re-worn until the butadiene has evaporated.
    C. Employees should be provided with and required to use splash 
proof safety goggles where liquid BD may contact the eyes.

                 VI. Housekeeping and Hygiene Facilities

    For purposes of complying with 29 CFR 1910.141, the following items 
should be emphasized:
    A. The workplace should be kept clean, orderly, and in a sanitary 
condition.
    B. Adequate washing facilities with hot and cold water are to be 
provided and maintained in a sanitary condition.

                       VII. Additional Precautions

    A. Store BD in tightly closed containers in a cool, well-ventilated 
area and take all necessary precautions to avoid any explosion hazard.
    B. Non-sparking tools must be used to open and close metal 
containers. These containers must be effectively grounded.
    C. Do not incinerate BD cartridges, tanks or other containers.
    D. Employers must advise employees of all areas and operations where 
exposure to BD might occur.

  Appendix C to Sec. 1910.1051--Medical Screening and Surveillance for 
                      1,3-Butadiene (Non-Mandatory)

      I. Basis for Medical Screening and Surveillance Requirements

                      A. Route of Entry Inhalation

                              B. Toxicology

    Inhalation of BD has been linked to an increased risk of cancer, 
damage to the reproductive organs, and fetotoxicity. Butadiene can be 
converted via oxidation to epoxybutene and diepoxybutane, two genotoxic 
metabolites that may play a role in the expression of BD's toxic 
effects.
    BD has been tested for carcinogenicity in mice and rats. Both 
species responded to BD exposure by developing cancer at multiple 
primary organ sites. Early deaths in mice were caused by malignant 
lymphomas, primarily lymphocytic type, originating in the thymus.
    Mice exposed to BD have developed ovarian or testicular atrophy. 
Sperm head morphology tests also revealed abnormal sperm in mice exposed 
to BD; lethal mutations were found in a dominant lethal test. In light 
of these results in animals, the possibility that BD may adversely 
affect the reproductive systems of male and female workers must be 
considered.
    Additionally, anemia has been observed in animals exposed to 
butadiene. In some cases, this anemia appeared to be a primary response 
to exposure; in other cases, it may have been secondary to a neoplastic 
response.

                             C. Epidemiology

    Epidemiologic evidence demonstrates that BD exposure poses an 
increased risk of leukemia. Mild alterations of hematologic parameters 
have also been observed in synthetic rubber workers exposed to BD.

                  II. Potential Adverse Health Effects

                                A. Acute

    Skin contact with liquid BD causes characteristic burns or 
frostbite. BD is gaseous form can irritate the eyes, nasal passages, 
throat, and lungs. Blurred vision, coughing, and drowsiness may also 
occur. Effects are mild at 2,000 ppm and pronounced at 8,000 ppm for 
exposures occurring over the full workshift.
    At very high concentrations in air, BD is an anesthetic, causing 
narcosis, respiratory paralysis, unconsciousness, and death. Such

[[Page 412]]

concentrations are unlikely, however, except in an extreme emergency 
because BD poses an explosion hazard at these levels.

                               B. Chronic

    The principal adverse health effects of concern are BD-induced 
lymphoma, leukemia and potential reproductive toxicity. Anemia and other 
changes in the peripheral blood cells may be indicators of excessive 
exposure to BD.

                             C. Reproductive

    Workers may be concerned about the possibility that their BD 
exposure may be affecting their ability to procreate a healthy child. 
For workers with high exposures to BD, especially those who have 
experienced difficulties in conceiving, miscarriages, or stillbirths, 
appropriate medical and laboratory evaluation of fertility may be 
necessary to determine if BD is having any adverse effect on the 
reproductive system or on the health of the fetus.

              III. Medical Screening Components At-A-Glance

                         A. Health Questionnaire

    The most important goal of the health questionnaire is to elicit 
information from the worker regarding potential signs or symptoms 
generally related to leukemia or other blood abnormalities. Therefore, 
physicians or other licensed health care professionals should be aware 
of the presenting symptoms and signs of lymphohematopoietic disorders 
and cancers, as well as the procedures necessary to confirm or exclude 
such diagnoses. Additionally, the health questionnaire will assist with 
the identification of workers at greatest risk of developing leukemia or 
adverse reproductive effects from their exposures to BD.
    Workers with a history of reproductive difficulties or a personal or 
family history of immune deficiency syndromes, blood dyscrasias, 
lymphoma, or leukemia, and those who are or have been exposed to 
medicinal drugs or chemicals known to affect the hematopoietic or 
lymphatic systems may be at higher risk from their exposure to BD. After 
the initial administration, the health questionnaire must be updated 
annually.

                      B. Complete Blood Count (CBC)

    The medical screening and surveillance program requires an annual 
CBC, with differential and platelet count, to be provided for each 
employee with BD exposure. This test is to be performed on a blood 
sample obtained by phlebotomy of the venous system or, if technically 
feasible, from a fingerstick sample of capillary blood. The sample is to 
be analyzed by an accredited laboratory.
    Abnormalities in a CBC may be due to a number of different 
etiologies. The concern for workers exposed to BD includes, but is not 
limited to, timely identification of lymphohematopoietic cancers, such 
as leukemia and non-Hodgkin's lymphoma. Abnormalities of portions of the 
CBC are identified by comparing an individual's results to those of an 
established range of normal values for males and females. A substantial 
change in any individual employee's CBC may also be viewed as 
``abnormal'' for that individual even if all measurements fall within 
the population-based range of normal values. It is suggested that a 
flowsheet for laboratory values be included in each employee's medical 
record so that comparisons and trends in annual CBCs can be easily made.
    A determination of the clinical significance of an abnormal CBC 
shall be the responsibility of the examining physician, other licensed 
health care professional, or medical specialist to whom the employee is 
referred. Ideally, an abnormal CBC should be compared to previous CBC 
measurements for the same employee, when available. Clinical common 
sense may dictate that a CBC value that is very slightly outside the 
normal range does not warrant medical concern. A CBC abnormality may 
also be the result of a temporary physical stressor, such as a transient 
viral illness, blood donation, or menorrhagia, or laboratory error. In 
these cases, the CBC should be repeated in a timely fashion, i.e., 
within 6 weeks, to verify that return to the normal range has occurred. 
A clinically significant abnormal CBC should result in removal of the 
employee from further exposure to BD. Transfer of the employee to other 
work duties in a BD-free environment would be the preferred 
recommendation.

                         C. Physical Examination

    The medical screening and surveillance program requires an initial 
physical examination for workers exposed to BD; this examination is 
repeated once every three years. The initial physical examination should 
assess each worker's baseline general health and rule out clinical signs 
of medical conditions that may be caused by or aggravated by 
occupational BD exposure. The physical examination should be directed at 
identification of signs of lymphohematopoietic disorders, including 
lymph node enlargement, splenomegaly, and hepatomegaly.
    Repeated physical examinations should update objective clinical 
findings that could be indicative of interim development of a 
lymphohematopoietic disorder, such as lymphoma, leukemia, or other blood 
abnormality. Physical examinations may also be provided on an as needed 
basis in order to follow up on a positive answer on the health 
questionnaire, or in response to an abnormal CBC. Physical examination 
of workers who

[[Page 413]]

will no longer be working in jobs with BD exposure are intended to rule 
out lymphohematopoietic disorders.
    The need for physical examinations for workers concerned about 
adverse reproductive effects from their exposure to BD should be 
identified by the physician or other licensed health care professional 
and provided accordingly. For these workers, such consultations and 
examinations may relate to developmental toxicity and reproductive 
capacity.
    Physical examination of workers acutely exposed to significant 
levels of BD should be especially directed at the respiratory system, 
eyes, sinuses, skin, nervous system, and any region associated with 
particular complaints. If the worker has received a severe acute 
exposure, hospitalization may be required to assure proper medical 
management. Since this type of exposure may place workers at greater 
risk of blood abnormalities, a CBC must be obtained within 48 hours and 
repeated at one, two, and three months.

  Appendix D to Sec. 1910.1051--Sampling and Analytical Method for 1,3-
                        Butadiene (Non-Mandatory)

    OSHA Method No.: 56.
    Matrix: Air.
    Target concentration: 1 ppm (2.21 mg/m\3\)
    Procedure: Air samples are collected by drawing known volumes of air 
through sampling tubes containing charcoal adsorbent which has been 
coated with 4-tert-butylcatechol. The samples are desorbed with carbon 
disulfide and then analyzed by gas chromatography using a flame 
ionization detector.
    Recommended sampling rate and air volume: 0.05 L/min and 3 L.
    Detection limit of the overall procedure: 90 ppb (200 ug/m \3\) 
(based on 3 L air volume).
    Reliable quantitation limit: 155 ppb (343 ug/m \3\) (based on 3 L 
air volume).
    Standard error of estimate at the target concentration: 6.5%.
    Special requirements: The sampling tubes must be coated with 4-tert-
butylcatechol. Collected samples should be stored in a freezer.
    Status of method: A sampling and analytical method has been 
subjected to the established evaluation procedures of the Organic 
Methods Evaluation Branch, OSHA Analytical Laboratory, Salt Lake City, 
Utah 84165.

                             1.  Background

    This work was undertaken to develop a sampling and analytical 
procedure for BD at 1 ppm. The current method recommended by OSHA for 
collecting BD uses activated coconut shell charcoal as the sampling 
medium (Ref. 5.2). This method was found to be inadequate for use at low 
BD levels because of sample instability.
    The stability of samples has been significantly improved through the 
use of a specially cleaned charcoal which is coated with 4-tert-
butylcatechol (TBC). TBC is a polymerization inhibitor for BD (Ref. 
5.3).

                          1.1.1  Toxic effects

    Symptoms of human exposure to BD include irritation of the eyes, 
nose and throat. It can also cause coughing, drowsiness and fatigue. 
Dermatitis and frostbite can result from skin exposure to liquid BD. 
(Ref. 5.1)
    NIOSH recommends that BD be handled in the workplace as a potential 
occupational carcinogen. This recommendation is based on two inhalation 
studies that resulted in cancers at multiple sites in rats and in mice. 
BD has also demonstrated mutagenic activity in the presence of a liver 
microsomal activating system. It has also been reported to have adverse 
reproductive effects. (Ref. 5.1)

                  1.1.2.  Potential workplace exposure

    About 90% of the annual production of BD is used to manufacture 
styrene-butadiene rubber and Polybutadiene rubber. Other uses include: 
Polychloroprene rubber, acrylonitrile butadiene-stryene resins, nylon 
intermediates, styrene-butadiene latexes, butadiene polymers, 
thermoplastic elastomers, nitrile resins, methyl methacrylate-butadiene 
styrene resins and chemical intermediates. (Ref. 5.1)

                 1.1.3.  Physical properties (Ref. 5.1)

    CAS No.: 106-99-0
    Molecular weight: 54.1
    Appearance: Colorless gas
    Boiling point: -4.41  deg.C (760 mm Hg)
    Freezing point: -108.9  deg.C
    Vapor pressure: 2 atm @ 15.3  deg.C; 5 atm @ 47  deg.C
    Explosive limits: 2 to 11.5% (by volume in air)
    Odor threshold: 0.45 ppm
    Structural formula: H2 C:CHCH:CH2
    Synonyms: BD; biethylene; bivinyl; butadiene; divinyl; buta-1,3-
diene; alpha-gamma-butadiene; erythrene; NCI-C50602; pyrrolylene; 
vinylethylene.

                     1.2.  Limit defining parameters

    The analyte air concentrations listed throughout this method are 
based on an air volume of 3 L and a desorption volume of 1 mL. Air 
concentrations listed in ppm are referenced to 25  deg.C and 760 mm Hg.

           1.2.1.  Detection limit of the analytical procedure

    The detection limit of the analytical procedure was 304 pg per 
injection. This was the amount of BD which gave a response relative to 
the interferences present in a standard.

[[Page 414]]

            1.2.2.  Detection limit of the overall procedure

    The detection limit of the overall procedure was 0.60 [mu]g per 
sample (90 ppb or 200 [mu]g/m3). This amount was determined 
graphically. It was the amount of analyte which, when spiked on the 
sampling device, would allow recovery approximately equal to the 
detection limit of the analytical procedure.

                   1.2.3.  Reliable quantitation limit

    The reliable quantitation limit was 1.03 [mu]g per sample (155 ppb 
or 343 [mu]g/m3). This was the smallest amount of analyte 
which could be quantitated within the limits of a recovery of at least 
75% and a precision (1.96 SD) of 25% or better.

                    1.2.4.  Sensitivity 1
---------------------------------------------------------------------------

    \1\ The reliable quantitation limit and detection limits reported in 
the method are based upon optimization of the instrument for the 
smallest possible amount of analyte. When the target concentration of an 
analyte is exceptionally higher than these limits, they may not be 
attainable at the routine operation parameters.
---------------------------------------------------------------------------

    The sensitivity of the analytical procedure over a concentration 
range representing 0.6 to 2 times the target concentration, based on the 
recommended air volume, was 387 area units per [mu]g/mL. This value was 
determined from the slope of the calibration curve. The sensitivity may 
vary with the particular instrument used in the analysis.

                            1.2.5.  Recovery

    The recovery of BD from samples used in storage tests remained above 
77% when the samples were stored at ambient temperature and above 94% 
when the samples were stored at refrigerated temperature. These values 
were determined from regression lines which were calculated from the 
storage data. The recovery of the analyte from the collection device 
must be at least 75% following storage.

               1.2.6.  Precision (analytical method only)

    The pooled coefficient of variation obtained from replicate 
determinations of analytical standards over the range of 0.6 to 2 times 
the target concentration was 0.011.

                  1.2.7.  Precision (overall procedure)

    The precision at the 95% confidence level for the refrigerated 
temperature storage test was 12.7%. This value includes an 
additional 5% for sampling error. The overall procedure must 
provide results at the target concentrations that are 25% at 
the 95% confidence level.

                         1.2.8.  Reproducibility

    Samples collected from a controlled test atmosphere and a draft copy 
of this procedure were given to a chemist unassociated with this 
evaluation. The average recovery was 97.2% and the standard deviation 
was 6.2%.

                          2. Sampling procedure

                             2.1.  Apparatus

    2.1.1.  Samples are collected by use of a personal sampling pump 
that can be calibrated to within 5% of the recommended 0.05 
L/min sampling rate with the sampling tube in line.
    2.1.2.  Samples are collected with laboratory prepared sampling 
tubes. The sampling tube is constructed of silane-treated glass and is 
about 5-cm long. The ID is 4 mm and the OD is 6 mm. One end of the tube 
is tapered so that a glass wool end plug will hold the contents of the 
tube in place during sampling. The opening in the tapered end of the 
sampling tube is at least one-half the ID of the tube (2 mm). The other 
end of the sampling tube is open to its full 4-mm ID to facilitate 
packing of the tube. Both ends of the tube are fire-polished for safety. 
The tube is packed with 2 sections of pretreated charcoal which has been 
coated with TBC. The tube is packed with a 50-mg backup section, located 
nearest the tapered end, and with a 100-mg sampling section of charcoal. 
The two sections of coated adsorbent are separated and retained with 
small plugs of silanized glass wool. Following packing, the sampling 
tubes are sealed with two \7/32\ inch OD plastic end caps. Instructions 
for the pretreatment and coating of the charcoal are presented in 
Section 4.1 of this method.

                             2.2.  Reagents

    None required.

                             2.3.  Technique

    2.3.1.  Properly label the sampling tube before sampling and then 
remove the plastic end caps.
    2.3.2.  Attach the sampling tube to the pump using a section of 
flexible plastic tubing such that the larger front section of the 
sampling tube is exposed directly to the atmosphere. Do not place any 
tubing ahead of the sampling tube. The sampling tube should be attached 
in the worker's breathing zone in a vertical manner such that it does 
not impede work performance.
    2.3.3.  After sampling for the appropriate time, remove the sampling 
tube from the pump and then seal the tube with plastic end caps. Wrap 
the tube lengthwise.
    2.3.4.  Include at least one blank for each sampling set. The blank 
should be handled in the same manner as the samples with the exception 
that air is not drawn through it.

[[Page 415]]

    2.3.5.  List any potential interferences on the sample data sheet.
    2.3.6.   The samples require no special shipping precautions under 
normal conditions. The samples should be refrigerated if they are to be 
exposed to higher than normal ambient temperatures. If the samples are 
to be stored before they are shipped to the laboratory, they should be 
kept in a freezer. The samples should be placed in a freezer upon 
receipt at the laboratory.

                           2.4.  Breakthrough

    (Breakthrough was defined as the relative amount of analyte found on 
the backup section of the tube in relation to the total amount of 
analyte collected on the sampling tube. Five-percent breakthrough 
occurred after sampling a test atmosphere containing 2.0 ppm BD for 90 
min at 0.05 L/min. At the end of this time 4.5 L of air had been sampled 
and 20.1 [mu]g of the analyte was collected. The relative humidity of 
the sampled air was 80% at 23  deg.C.)
    Breakthrough studies have shown that the recommended sampling 
procedure can be used at air concentrations higher than the target 
concentration. The sampling time, however, should be reduced to 45 min 
if both the expected BD level and the relative humidity of the sampled 
air are high.

                       2.5.  Desorption efficiency

    The average desorption efficiency for BD from TBC coated charcoal 
over the range from 0.6 to 2 times the target concentration was 96.4%. 
The efficiency was essentially constant over the range studied.

             2.6.  Recommended air volume and sampling rate

    2.6.1.   The recommended air volume is 3L.
    2.6.2.   The recommended sampling rate is 0.05 L/min for 1 hour.

                           2.7.  Interferences

    There are no known interferences to the sampling method.

                        2.8.  Safety precautions

    2.8.1.   Attach the sampling equipment to the worker in such a 
manner that it will not interfere with work performance or safety.
    2.8.2.   Follow all safety practices that apply to the work area 
being sampled.

                        3.  Analytical procedure

                             3.1.  Apparatus

    3.1.1.   A gas chromatograph (GC), equipped with a flame ionization 
detector (FID).2
---------------------------------------------------------------------------

    \2\ A Hewlett-Packard Model 5840A GC was used for this evaluation. 
Injections were performed using a Hewlett-Packard Model 7671A automatic 
sampler.
---------------------------------------------------------------------------

    3.1.2.   A GC column capable of resolving the analytes from any 
interference.3
---------------------------------------------------------------------------

    \3\ A 20-ft x \1/8\-inch OD stainless steel GC column containing 20% 
FFAP on 80/100 mesh Chromabsorb W-AW-DMCS was used for this evaluation.
---------------------------------------------------------------------------

    3.1.3.   Vials, glass 2-mL with Teflon-lined caps.
    3.1.4.   Disposable Pasteur-type pipets, volumetric flasks, pipets 
and syringes for preparing samples and standards, making dilutions and 
performing injections.

                             3.2.  Reagents

    3.2.1.   Carbon disulfide.4
---------------------------------------------------------------------------

    \4\ Fisher Scientific Company A.C.S. Reagent Grade solvent was used 
in this evaluation.
---------------------------------------------------------------------------

    The benzene contaminant that was present in the carbon disulfide was 
used as an internal standard (ISTD) in this evaluation.
    3.2.2.   Nitrogen, hydrogen and air, GC grade.
    3.2.3.   BD of known high purity.5
---------------------------------------------------------------------------

    \5\ Matheson Gas Products, CP Grade 1,3-butadiene was used in this 
study.
---------------------------------------------------------------------------

                       3.3.  Standard preparation

    3.3.1.   Prepare standards by diluting known volumes of BD gas with 
carbon disulfide. This can be accomplished by injecting the appropriate 
volume of BD into the headspace above the 1-mL of carbon disulfide 
contained in sealed 2-mL vial. Shake the vial after the needle is 
removed from the septum.6
---------------------------------------------------------------------------

    \6\ A standard containing 7.71 [mu]g/mL (at ambient temperature and 
pressure) was prepared by diluting 4 [mu]L of the gas with 1-mL of 
carbon disulfide.
---------------------------------------------------------------------------

    3.3.2.   The mass of BD gas used to prepare standards can be 
determined by use of the following equations:

MV = (760/BP)(273+t)/(273)(22.41)

Where:

MV = ambient molar volume
BP = ambient barometric pressure
T = ambient temperature
[mu]g/[mu]L = 54.09/MV
[mu]g/standard = ([mu]g/[mu]L)([mu]L) BD used to prepare the standard

                        3.4.  Sample preparation

    3.4.1.   Transfer the 100-mg section of the sampling tube to a 2-mL 
vial. Place the 50-mg section in a separate vial. If the glass wool 
plugs contain a significant amount of charcoal, place them with the 
appropriate sampling tube section.
    3.4.2.   Add 1-mL of carbon disulfide to each vial.

[[Page 416]]

    3.4.3.   Seal the vials with Teflon-lined caps and then allow them 
to desorb for one hour. Shake the vials by hand vigorously several times 
during the desorption period.
    3.4.4.   If it is not possible to analyze the samples within 4 
hours, separate the carbon disulfide from the charcoal, using a 
disposable Pasteur-type pipet, following the one hour. This separation 
will improve the stability of desorbed samples.
    3.4.5.   Save the used sampling tubes to be cleaned and repacked 
with fresh adsorbent.

                             3.5.  Analysis

    3.5.1.   GC Conditions
    Column temperature: 95  deg.C
    Injector temperature: 180  deg.C
    Detector temperature: 275  deg.C
    Carrier gas flow rate: 30 mL/min
    Injection volume: 0.80 [mu]L
    GC column: 20-ft x \1/8\-in OD stainless steel GC column containing 
20%
    FFAP on 80/100 Chromabsorb W-AW-DMCS.
    3.5.2.   Chromatogram. See Section 4.2.
    3.5.3.   Use a suitable method, such as electronic or peak heights, 
to measure detector response.
    3.5.4.   Prepare a calibration curve using several standard 
solutions of different concentrations. Prepare the calibration curve 
daily. Program the integrator to report the results in [mu]g/mL.
    3.5.5.   Bracket sample concentrations with standards.

                    3.6.  Interferences (analytical)

    3.6.1.   Any compound with the same general retention time as the 
analyte and which also gives a detector response is a potential 
interference. Possible interferences should be reported by the 
industrial hygienist to the laboratory with submitted samples.
    3.6.2.   GC parameters (temperature, column, etc.) may be changed to 
circumvent interferences.
    3.6.3.   A useful means of structure designation is GC/MS. It is 
recommended that this procedure be used to confirm samples whenever 
possible.

                           3.7.  Calculations

    3.7.1.   Results are obtained by use of calibration curves. 
Calibration curves are prepared by plotting detector response against 
concentration for each standard. The best line through the data points 
is determined by curve fitting.
    3.7.2.   The concentration, in ug/mL, for a particular sample is 
determined by comparing its detector response to the calibration curve. 
If any analyte is found on the backup section, this amount is added to 
the amount found on the front section. Blank corrections should be 
performed before adding the results together.
    3.7.3.   The BD air concentration can be expressed using the 
following equation:

mg/m \3\ = (A)(B)/(C)(D)

Where:

A = [mu]g/mL from Section 3.7.2
B = volume
C = L of air sampled
D = efficiency

    3.7.4.   The following equation can be used to convert results in 
mg/m \3\ to ppm:
ppm = (mg/m \3\)(24.46)/54.09

Where:

mg/m \3\ = result from Section 3.7.3.
24.46 = molar volume of an ideal gas at 760 mm Hg and 25  deg.C.

                  3.8.  Safety precautions (analytical)

    3.8.1.   Avoid skin contact and inhalation of all chemicals.
    3.8.2.   Restrict the use of all chemicals to a fume hood whenever 
possible.
    3.8.3.   Wear safety glasses and a lab coat in all laboratory areas.

                       4.  Additional Information

 4.1.  A procedure to prepare specially cleaned charcoal coated with TBC

    4.1.1.   Apparatus.
    4.1.1.1.   Magnetic stirrer and stir bar.
    4.1.1.2.   Tube furnace capable of maintaining a temperature of 700 
deg.C and equipped with a quartz tube that can hold 30 g of 
charcoal.8
---------------------------------------------------------------------------

    \8\ A Lindberg Type 55035 Tube furnace was used in this evaluation.
---------------------------------------------------------------------------

    4.1.1.3.   A means to purge nitrogen gas through the charcoal inside 
the quartz tube.
    4.1.1.4.   Water bath capable of maintaining a temperature of 60 
deg.C.
    4.1.1.5.   Miscellaneous laboratory equipment: One-liter vacuum 
flask, 1-L Erlenmeyer flask, 350-M1 Buchner funnel with a coarse fitted 
disc, 4-oz brown bottle, rubber stopper, Teflon tape etc.

                            4.1.2.  Reagents

    4.1.2.1.   Phosphoric acid, 10% by weight, in water.9
---------------------------------------------------------------------------

    \9\ Baker Analyzed'' Reagent grade was diluted with water for use in 
this evaluation.
---------------------------------------------------------------------------

    4.1.2.2.  4-tert-Butylcatechol (TBC).10
---------------------------------------------------------------------------

    \10\ The Aldrich Chemical Company 99% grade was used in this 
evaluation.
---------------------------------------------------------------------------

    4.1.2.3.   Specially cleaned coconut shell charcoal, 20/40 
mesh.11
---------------------------------------------------------------------------

    \11\ Specially cleaned charcoal was obtained from Supelco, Inc. for 
use in this evaluation. The cleaning process used by Supelco is 
proprietary.
---------------------------------------------------------------------------

    4.1.2.4.   Nitrogen gas, GC grade.
    4.1.3.   Procedure.

[[Page 417]]

    Weigh 30g of charcoal into a 500-mL Erlenmeyer flask. Add about 250 
mL of 10% phosphoric acid to the flask and then swirl the mixture. Stir 
the mixture for 1 hour using a magnetic stirrer. Filter the mixture 
using a fitted Buchner funnel. Wash the charcoal several times with 250-
mL portions of deionized water to remove all traces of the acid. 
Transfer the washed charcoal to the tube furnace quartz tube. Place the 
quartz tube in the furnace and then connect the nitrogen gas purge to 
the tube. Fire the charcoal to 700  deg.C. Maintain that temperature for 
at least 1 hour. After the charcoal has cooled to room temperature, 
transfer it to a tared beaker. Determine the weight of the charcoal and 
then add an amount of TBC which is 10% of the charcoal, by weight.
    CAUTION-TBC is toxic and should only be handled in a fume hood while 
wearing gloves.
    Carefully mix the contents of the beaker and then transfer the 
mixture to a 4-oz bottle. Stopper the bottle with a clean rubber stopper 
which has been wrapped with Teflon tape. Clamp the bottle in a water 
bath so that the water level is above the charcoal level. Gently heat 
the bath to 60  deg.C and then maintain that temperature for 1 hour. 
Cool the charcoal to room temperature and then transfer the coated 
charcoal to a suitable container.
    The coated charcoal is now ready to be packed into sampling tubes. 
The sampling tubes should be stored in a sealed container to prevent 
contamination. Sampling tubes should be stored in the dark at room 
temperature. The sampling tubes should be segregated by coated adsorbent 
lot number.

                            4.2 Chromatograms

    The chromatograms were obtained using the recommended analytical 
method. The chart speed was set at 1 cm/min for the first three min and 
then at 0.2 cm/min for the time remaining in the analysis.
    The peak which elutes just before BD is a reaction product between 
an impurity on the charcoal and TBC. This peak is always present, but it 
is easily resolved from the analyte. The peak which elutes immediately 
before benzene is an oxidation product of TBC.

                              5. References

    5.1.  ``Current Intelligence Bulletin 41, 1,3-Butadiene'', U.S. 
Dept. of Health and Human Services, Public Health Service, Center for 
Disease Control, NIOSH.
    5.2.  ``NIOSH Manual of Analytical Methods'', 2nd ed; U.S. Dept. of 
Health Education and Welfare, National Institute for Occupational Safety 
and Health: Cincinnati, OH. 1977, Vol. 2, Method No. S91 DHEW (NIOSH) 
Publ. (US), No. 77-157-B.
    5.3.   Hawley, G.C., Ed. ``The Condensed Chemical Dictionary'', 8th 
ed.; Van Nostrand Rienhold Company: New York, 1971; 139.5.4. Chem. Eng. 
News (June 10, 1985), (63), 22-66.

                 Appendix E to Sec. 1910.1051 [Reserved]

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[61 FR 56831, Nov. 4, 1996, as amended at 63 FR 1294, Jan. 8, 1998; 67 
FR 67965, Nov. 7, 2002]

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