[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: 29CFR1910.1045]
[Page 315-333]
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. 1910.1045 Acrylonitrile.
(a) Scope and application. (1) This section applies to all
occupational exposures to acrylonitrile (AN), Chemical Abstracts Service
Registry No. 000107131, except as provided in paragraphs (a)(2) and
(a)(3) of this section.
(2) This section does not apply to exposures which result solely
from the processing, use, and handling of the following materials:
(i) ABS resins, SAN resins, nitrile barrier resins, solid nitrile
elastomers, and acrylic and modacrylic fibers, when these listed
materials are in the form of finished polymers, and products fabricated
from such finished polymers;
(ii) Materials made from and/or containing AN for which objective
data is reasonably relied upon to demonstrate that the material is not
capable of releasing AN in airborne concentrations in excess of 1 ppm as
an eight (8)-hour time-weighted average, under the expected conditions
of processing, use, and handling which will cause the greatest possible
release; and
(iii) Solid materials made from and/or containing AN which will not
be heated above 170 deg.F during handling, use, or processing.
(3) An employer relying upon exemption under paragraph (a)(2)(ii)
shall maintain records of the objective data supporting that exemption,
and of the basis of the employer's reliance on the data, as provided in
paragraph (q) of this section.
(b) Definitions. Acrylonitrile or AN means acrylonitrile monomer,
chemical formula CH2=CHCN.
Action level means a concentration of AN of 1 ppm 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 authorized by the
employer whose duties require the person to enter a regulated area, or
any person entering such an area as a designated representative of
employees for the purpose of exercising the opportunity to observe
monitoring procedures under paragraph (r) of this section.
Decontamination means treatment of materials and surfaces by water
washdown, ventilation, or other means, to assure that the materials will
not expose employees to airborne concentrations of AN above 1 means the
Director, National Institute for Occupational Safety and Health, U.S.
Department of Health and Human Services, or designee.
Emergency means any occurrence such as, but not limited to,
equipment failure, rupture of containers, or failure of control
equipment, which results in an unexpected massive release of AN.
Liquid AN means AN monomer in liquid form, and liquid or semiliquid
polymer intermediates, including slurries, suspensions, emulsions, and
solutions, produced during the polymerization of AN.
OSHA Area Office means the Area Office of the Occupational Safety
and Health Administration having jurisdiction over the geographic area
where the affected workplace is located.
(c) Permissible exposure limits--(1) Inhalation. (i) Time weighted
average limit (TWA). The employer shall assure that no employee is
exposed to an airborne concentration of acrylonitrile in excess of two
(2) parts acrylonitrile per million parts of air (2 ppm) as an eight
(8)-hour time-weighted average.
(ii) Ceiling limit. The employer shall assure that no employee is
exposed to
[[Page 316]]
an airborne concentration of acrylonitrile in excess of ten (10) ppm as
averaged over any fifteen (15)-minute period during the work day.
(2) Dermal and eye exposure. The employer shall assure that no
employee is exposed to skin contact or eye contact with liquid AN.
(d) Notification of regulated areas and emergencies--(1) Regulated
areas. Within thirty (30) days following the establishment of a
regulated area pursuant to paragraph (f) of this section, the employer
shall report the following information to the OSHA Area Office:
(i) The address and location of each establishment which has one or
more regulated areas;
(ii) The locations, within the establishment, of each regulated
area;
(iii) A brief description of each process or operation which results
in employee exposure to AN in regulated areas; and
(iv) The number of employees engaged in each process or operation
within each regulated area which results in exposure to AN, and an
estimate of the frequency and degree of exposure that occurs.
Whenever there has been a significant change in the information
required to be reported by this paragraph, the employer shall promptly
provide the new information to the OSHA Area Office.
(2) Emergencies. Emergencies, and the facts obtainable at that time,
shall be reported within seventy-two (72) hours of the initial
occurrence to the OSHA Area Office. Upon request of the OSHA Area
Office; the employer shall submit additional information in writing
relevant to the nature and extent of employee exposures and measures
taken to prevent future emergencies of a similar nature.
(e) Exposure monitoring--(1) General. (i) Determinations of airborne
exposure levels shall be made from air samples that are representative
of each employee's exposure to AN over an eight (8)-hour period.
(ii) For the purposes of this section, employee exposure is that
exposure which would occur if the employee were not using a respirator.
(2) Initial monitoring. Each employer who has a place of employment
in which AN is present shall monitor each such workplace and work
operation to accurately determine the airborne concentrations of AN to
which employees may be exposed.
(3) Frequency. (i) If the monitoring required by this section
reveals employee exposure to be below the action level, the employer may
discontinue monitoring for that employee.
(ii) If the monitoring required by this section reveals employee
exposure to be at or above the action level but below the permissible
exposure limits, the employer shall repeat such monitoring for each such
employee at least quarterly. The employer shall continue these quarterly
measurements until at least two consecutive measurements taken at least
seven (7) days apart, are below the action level, and thereafter the
employer may discontinue monitoring for that employee.
(iii) If the monitoring required by this section reveals employee
exposure to be in excess of the permissible exposure limits, the
employer shall repeat these determinations for each such employee at
least monthly. The employer shall continue these monthly measurements
until at least two consecutive measurements, taken at least seven (7)
days apart, are below the permissible exposure limits, and thereafter
the employer shall monitor at least quarterly.
(4) Additional monitoring. Whenever there has been a production,
process, control, or personnel change which may result in new or
additional exposures to AN, or whenever the employer has any other
reason to suspect a change which may result in new or additional
exposures to AN, additional monitoring which complies with this
paragraph shall be conducted.
(5) Employee notification. (i) Within five (5) working days after
the receipt of the results of monitoring required by this paragraph, the
employer shall notify each employee in writing of the results which
represent that employee's exposure.
(ii) Whenever the results indicate that the representative employee
exposure exceeds the permissible exposure limits, the employer shall
include in the written notice a statement that the permissible exposure
limits were
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exceeded and a description of the corrective action being taken to
reduce exposure to or below the permissible exposure limits.
(6) Accuracy of measurement. The method of measurement of employee
exposures shall be accurate to a confidence level of 95 percent, to
within plus or minus 35 percent for concentrations of AN at or above the
permissible exposure limits, and plus or minus 50 percent for
concentrations of AN below the permissible exposure limits.
(f) Regulated areas. (1) The employer shall establish regulated
areas where AN concentrations are in excess of the permissible exposure
limits.
(2) Regulated areas shall be demarcated and segregated from the rest
of the workplace, in any manner that minimizes the number of persons who
will be exposed to AN.
(3) Access to regulated areas shall be limited to authorized persons
or to persons otherwise authorized by the act or regulations issued
pursuant thereto.
(4) The employer shall assure that food or beverages are not present
or consumed, tobacco products are not present or used, and cosmetics are
not applied in the regulated area.
(g) Methods of compliance--(1) Engineering and work practice
controls. (i) By November 2, 1980, the employer shall institute
engineering and work practice controls to reduce and maintain employee
exposures to AN, to or below the permissible exposure limits, except to
the extent that the employer establishes that such controls are not
feasible.
(ii) Wherever the engineering and work practice controls which can
be instituted are not sufficient to reduce employee exposures to or
below the permissible exposure limits, the employer shall nonetheless
use them to reduce exposures to the lowest levels achievable by these
controls, and shall supplement them by the use of respiratory protection
which complies with the requirements of paragraph (h) of this section.
(2) Compliance program. (i) The employer shall establish and
implement a written program to reduce employee exposures to or below the
permissible exposure limits solely by means of engineering and work
practice controls, as required by paragraph (g)(1) of this section.
(ii) Written plans for these compliance programs shall include at
least the following:
(A) A description of each operation or process resulting in employee
exposure to AN above the permissible exposure limits;
(B) An outline of the nature of the engineering controls and work
practices to be applied to the operation or process in question;
(C) A report of the technology considered in meeting the permissible
exposure limits;
(D) A schedule for implementation of engineering and work practice
controls for the operation or process, which shall project completion no
later than November 2, 1980; and
(E) Other relevant information.
(iii) The employer shall complete the steps set forth in the
compliance program by the dates in the schedule.
(iv) Written plans shall be submitted upon request to the Assistant
Secretary and the Director, and shall be available at the worksite for
examination and copying by the Assistant Secretary, the Director, or any
affected employee or representative.
(v) The plans required by this paragraph shall be revised and
updated at least every six (6) months to reflect the current status of
the program.
(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) Work operations, such as maintenance and repair activities or
reactor cleaning, for which the employer establishes that engineering
and work-practice controls are not feasible.
(iii) Work operations for which feasible engineering and work-
practice controls are not yet sufficient to reduce employee exposure to
or below the permissible exposure limits.
(iv) Emergencies.
(2) Respirator program. (i) The employer must implement a
respiratory
[[Page 318]]
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 (chemical-cartridge or chemical-
canister types) are used:
(A) The air-purifying canister or cartridge must be replaced prior
to the expiration of its service life or at the completion of each
shift, whichever occurs first.
(B) A label must be attached to the cartridge or canister to
indicate the date and time at which it is first installed on the
respirator.
(3) Respirator selection. The employer must select the appropriate
respirator from Table I of this section.
Table I--Respiratory Protection for Acrylonitrile (AN)
------------------------------------------------------------------------
Concentration of AN or
condition of use Respirator type
------------------------------------------------------------------------
(a) Less than or equal to 20 (1) Chemical cartridge respirator with
ppm. organic vapor cartridge(s) and half-mask
facepiece; or
(2) Supplied air respirator with half-
mask facepiece.
(b) Less than or equal to 100 (1) Full facepiece respirator with (A)
ppm or maximum use organic vapor cartridges, (B) organic
concentration (MUC) of vapor gas mask chin-style, or (C)
cartridges or canisters, organic vapor gas mask canister, front-
whichever is lower. or back-mounted;
(2) Supplied air respirator with full
facepiece; or
(3) Self-contained breathing apparatus
with full facepiece.
(c) Less than or equal to (1) Supplied air respirator operated in
4,000 ppm. the positive pressure mode with full
facepiece, helmet, suit, or hood.
(d) Greater than 4,000 ppm or (1) Supplied air and auxiliary self-
unknown concentration. contained breathing apparatus with full
facepiece in positive pressure mode; or
(2) Self-contained breathing apparatus
with full facepiece in positive pressure
mode.
(e) Firefighting............. Self-contained breathing apparatus with
full facepiece in positive pressure
mode.
(f) Escape................... (1) Any organic vapor respirator, or
(2) Any self-contained breathing
apparatus.
------------------------------------------------------------------------
(i) Emergency situations--(1) Written plans. (i) A written plan for
emergency situations shall be developed for each workplace where liquid
AN is present. Appropriate portions of the plan shall be implemented in
the event of an emergency.
(ii) The plan shall specifically provide that employees engaged in
correcting emergency conditions shall be equipped as required in
paragraph (h) of this section until the emergency is abated.
(iii) Employees not engaged in correcting the emergency shall be
evacuated from the area and shall not be permitted to return until the
emergency is abated.
(2) Alerting employees. Where there is the possibility of employee
exposure to AN in excess of the ceiling limit, a general alarm shall be
installed and used to promptly alert employees of such occurrences.
(j) Protective clothing and equipment--(1) Provision and use. Where
eye or skin contact with liquid AN may occur, the employer shall provide
at no cost to the employee, and assure that employees wear, impermeable
protective clothing or other equipment to protect any area of the body
which may come in contact with liquid AN. The provision of
Secs. 1910.132 and 1910.133 shall be complied with.
(2) Cleaning and replacement. (i) The employer shall clean, launder,
maintain, or replace protective clothing and equipment required by this
section as needed to maintain their effectiveness.
(ii) The employer shall assure that impermeable protective clothing
which contacts or is likely to have contacted liquid AN shall be
decontaminated before being removed by the employee.
(iii) The employer shall assure that an employee whose
nonimpermeable clothing becomes wetted with liquid AN shall immediately
remove that clothing and proceed to shower. The clothing shall be
decontaminated before it is removed from the regulated area.
(iv) The employer shall assure that no employee removes protective
clothing or equipment from the change room, except for those employees
authorized to do so for the purpose of laundering, maintenance, or
disposal.
[[Page 319]]
(v) The employer shall inform any person who launders or cleans
protective clothing or equipment of the potentially harmful effects of
exposure to AN.
(k) Housekeeping. (1) All surfaces shall be maintained free of
visible accumulations of liquid AN.
(2) For operations involving liquid AN, the employer shall institute
a program for detecting leaks and spills of liquid AN, including regular
visual inspections.
(3) Where spills of liquid AN are detected, the employer shall
assure that surfaces contacted by the liquid AN are decontaminated.
Employees not engaged in decontamination activities shall leave the area
of the spill, and shall not be permitted in the area until
decontamination is completed.
(l) Waste disposal. AN waste, scrap, debris, bags, containers, or
equipment shall be decontaminated before being incorporated in the
general waste disposal system.
(m) Hygiene facilities and practices. (1) Where employees are
exposed to airborne concentrations of AN above the permissible exposure
limits, or where employees are required to wear protective clothing or
equipment pursuant to paragraph (j) of this section, the facilities
required by 29 CFR 1910.141, including clean change rooms and shower
facilities, shall be provided by the employer for the use of those
employees, and the employer shall assure that the employees use the
facilities provided.
(2) The employer shall assure that employees wearing protective
clothing or equipment for protection from skin contact with liquid AN
shall shower at the end of the work shift.
(3) The employer shall assure that, in the event of skin or eye
exposure to liquid AN, the affected employee shall shower immediately to
minimize the danger of skin absorption.
(4) The employer shall assure that employees working in the
regulated area wash their hands and faces prior to eating.
(n) Medical surveillance--(1) General. (i) The employer shall
institute a program of medical surveillance for each employee who is or
will be exposed to AN at or above the action level, without regard to
the use of respirators. The employer shall provide each such employee
with an opportunity for medical examinations and tests in accordance
with this paragraph.
(ii) The employer shall assure that all medical examinations and
procedures are performed by or under the supervision of a licensed
physician, and that they shall be provided without cost to the employee.
(2) Initial examinations. At the time of initial assignment, or upon
institution of the medical surveillance program, the employer shall
provide each affected employee an opportunity for a medical examination,
including at least the following elements:
(i) A work history and medical history with special attention to
skin, respiratory, and gastrointestinal systems, and those nonspecific
symptoms, such as headache, nausea, vomiting, dizziness, weakness, or
other central nervous system dysfunctions that may be associated with
acute or with chronic exposure to AN;
(ii) A complete physical examination giving particular attention to
the peripheral and central nervous system, gastrointestinal system,
respiratory system, skin, and thyroid;
(iii) A 14- by 17-inch posteroanterior chest X-ray; and
(iv) Further tests of the intestinal tract, including fecal occult
blood screening, for all workers 40 years of age or older, and for any
other affected employees for whom, in the opinion of the physician, such
testing is appropriate.
(3) Periodic examinations. (i) The employer shall provide the
examinations specified in paragraph (n)(2) of this section at least
annually for all employees specified in paragraph (n)(1) of this
section.
(ii) If an employee has not had the examination specified in
paragraph (n)(2) of this section within 6 months preceding termination
of employment, the employer shall make such examination available to the
employee prior to such termination.
(4) Additional examinations. If the employee for any reason develops
signs or symptoms which may be associated with exposure to AN, the
employer
[[Page 320]]
shall provide an appropriate examination and emergency medical
treatment.
(5) Information provided to the physician. The employer shall
provide the following information to the examining physician:
(i) A copy of this standard and its appendixes;
(ii) A description of the affected employee's duties as they relate
to the employee's exposure;
(iii) The employee's representative exposure level;
(iv) The employee's anticipated or estimated exposure level (for
preplacement examinations or in cases of exposure due to an emergency);
(v) A description of any personal protective equipment used or to be
used; and
(vi) Information from previous medical examinations of the affected
employee, which is not otherwise available to the examining physician.
(6) Physician's written opinion. (i) The employer shall obtain a
written opinion from the examining physician which shall include:
(A) The results of the medical examination and test performed;
(B) The physician's opinion as to whether the employee has any
detected medical condition(s) which would place the employee at an
increased risk of material impairment of the employee's health from
exposure to AN;
(C) Any recommended limitations upon the employee's exposure to AN
or upon the use of protective clothing and equipment such as
respirators; and
(D) A statement that the employee has been informed by the physician
of the results of the medical examination and any medical conditions
which require further examination or treatment.
(ii) The employer shall instruct the physician not to reveal in the
written opinion specific findings or diagnoses unrelated to occupational
exposure to AN.
(iii) The employer shall provide a copy of the written opinion to
the affected employee.
(o) Employee information and training--(1) Training program. (i) By
January 2, 1979, the employer shall institute a training program for and
assure the participation of all employees exposed to AN above the action
level, all employees whose exposures are maintained below the action
level by engineering and work practice controls, and all employees
subject to potential skin or eye contact with liquid AN.
(ii) Training shall be provided at the time of initial assignment,
or upon institution of the training program, and at least annually
thereafter, and the employer shall assure that each employee is informed
of the following:
(A) The information contained in appendixes A and B;
(B) The quantity, location, manner of use, release, or storage of
AN, and the specific nature of operations which could result in exposure
to AN, as well as any necessary protective steps;
(C) The purpose, proper use, and limitations of respirators and
protective clothing;
(D) The purpose and a description of the medical surveillance
program required by paragraph (n) of this section;
(E) The emergency procedures developed, as required by paragraph (i)
of this section;
(F) Engineering and work practice controls, their function, and the
employee's relationship to these controls; and
(G) A review of this standard.
(2) Access to training materials. (i) The employer shall make a copy
of this standard and its appendixes readily available to all affected
employees.
(ii) The employer shall provide, upon request, all materials
relating to the employee information and training program to the
Assistant Secretary and the Director.
(p) Signs and labels--(1) General. (i) The employer may use labels
or signs required by other statutes, regulations, or ordinances in
addition to, or in combination with, signs and labels required by this
paragraph.
(ii) The employer shall assure that no statement appears on or near
any sign or label required by this paragraph which contradicts or
detracts from the required sign or label.
(2) Signs. (i) The employer shall post signs to clearly indicate all
workplaces where AN concentrations exceed the
[[Page 321]]
permissable exposure limits. The signs shall bear the following legend:
DANGER
ACRYLONITRILE (AN)
CANCER HAZARD
AUTHORIZED PERSONNEL ONLY
RESPIRATORS MAY BE
REQUIRED
(ii) The employer shall assure that signs required by this paragraph
are illuminated and cleaned as necessary so that the legend is readily
visible.
(3) Labels. (i) The employer shall assure that precautionary labels
are affixed to all containers of liquid AN and AN-based materials not
exempted under paragraph (a)(2) of this standard. The employer shall
assure that the lables remain affixed when the materials are sold,
distributed, or otherwise leave the employer's workplace.
(ii) The employer shall assure that the precautionary labels
required by this paragraph are readily visible and legible. The labels
shall bear the following legend:
DANGER
CONTAINS ACRYLONITRILE (AN)
CANCER HAZARD
(q) Recordkeeping--(1) Objective data for exempted operations. (i)
Where the processing, use, and handling of materials made from or
containing AN are exempted pursuant to paragraph (a)(2)(ii) of this
section, the employer shall establish and maintain an accurate record of
objective data reasonably relied upon in support of the exemption.
(ii) This record shall include at least the following information:
(A) The material qualifying for exemption;
(B) The source of the objective data;
(C) The testing protocol, results of testing, and/or analysis of the
material for the release of AN;
(D) A description of the operation exempted and how the data
supports the exemption; and
(E) Other data relevant to the operations, materials, and processing
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 monitoring. (i) The employer shall establish and
maintain an accurate record of all monitoring required by paragraph (e)
of this section.
(ii) This record shall include:
(A) The dates, number, duration, and results of each of the samples
taken, including a description of the sampling procedure used to
determine representative employee exposure;
(B) A description of the sampling and analytical methods used and
the data relied upon to establish that the methods used meet the
accuracy and precision requirements of paragraph (e)(6) of this section;
(C) Type of respiratory protective devices worn, if any; and
(D) Name, social security number, and job classification of the
employee monitored and of all other employees whose exposure the
measurement is intended to represent.
(iii) The employer shall maintain this record for at least forty
(40) years, or for the duration of employment plus twenty (20) years,
whichever is longer.
(3) Medical surveillance. (i) The employer shall establish and
maintain an accurate record for each employee subject to medical
surveillance as required by paragraph (n) of this section.
(ii) This record shall include:
(A) A copy of the physician's written opinions;
(B) Any employee medical complaints related to exposure to AN;
(C) A copy of the information provided to the physician as required
by paragraph (n)(5) of this section; and
(D) A copy of the employee's medical and work history.
(iii) The employer shall assure that this record be maintained for
at least forty (40) years, or for the duration of employment plus twenty
(20) years, whichever is longer.
(4) Availability. (i) The employer shall make all records required
to be maintained by this section available, upon request, to the
Assistant Secretary and the Director for examination and copying.
(ii) Records required by paragraphs (q)(1) through (q)(3) of this
section shall be provided upon request to employees, designated
representatives, and the Assistant Secretary in accordance with 29 CFR
1910.20 (a) through (e)
[[Page 322]]
and (q) through (i). Records required by paragraph (q)(1) shall be
provided in the same manner as exposure monitoring records.
(5) Transfer of records. (i) Whenever the employer ceases to do
business, the successor employer shall receive and retain all records
required to be maintained by this section for the prescribed period.
(ii) Whenever the employer ceases to do business and there is no
successor employer to receive and retain the records for the prescribed
period, these records shall be transmitted to the Director.
(iii) At the expiration of the retention period for the records
required to be maintained pursuant to this section, the employer shall
notify the Director at least 3 months prior to the disposal of the
records, and shall transmit them to the Director upon request.
(iv) The employer shall also comply with any additional requirements
involving transfer of records set forth in 29 CFR 1910.20(h).
(r) Observation of monitoring--(1) Employee observation. The
employer shall provide affected employees, or their designated
representatives, an opportunity to observe any monitoring of employee
exposure to AN conducted pursuant to paragraph (e) of this section.
(2) Observation procedures. (i) Whenever observation of the
monitoring of employee exposure to AN requires entry into an area where
the use of protective clothing or equipment is required, the employer
shall provide the observer with personal protective clothing and
equipment required to be worn by employees working in the area, assure
the use of such clothing and equipment, and require the observer to
comply with all other applicable safety and health procedures.
(ii) Without interfering with the monitoring, observers shall be
entitled:
(A) To receive an explanation of the measurement procedures;
(B) To observe all steps related to the measurement of airborne
concentrations of AN performed at the place of exposure; and
(C) To record the results obtained.
(s) Effective date: (1) This section shall become effective November
2, 1978.
(2) Monitoring and medical surveillance conducted since January 17,
1978, under the provisions of the emergency temporary standard may be
relied upon by the employer to meet the initial monitoring and initial
medical surveillance requirements of this section.
(3) Training programs must be implemented by January 2, 1979.
(4) Engineering and work practice controls required by paragraph (g)
of this section shall be implemented no later than November 2, 1980.
(t) Appendixes. The information contained in the appendixes is not
intended, by itself, to create any additional obligation not otherwise
imposed, or to detract from any obligation.
Appendix A to Sec. 1910.1045--Substance Safety Data Sheet for
Acrylonitrile
i. Substance Identification
A. Substance: Acrylonitrile (CH2 CHCN).
B. Synonyms: Propenenitrile; vinyl cyanide; cyanoethylene; AN; VCN;
acylon; carbacryl; fumigrian; ventox.
C. Acrylonitrile can be found as a liquid or vapor, and can also be
found in polymer resins, rubbers, plastics, polyols, and other polymers
having acrylonitrile as a raw or intermediate material.
D. AN is used in the manufacture of acrylic and modiacrylic fibers,
acrylic plastics and resins, speciality polymers, nitrile rubbers, and
other organic chemicals. It has also been used as a fumigant.
E. Appearance and odor: Colorless to pale yellow liquid with a
pungent odor which can only be detected at concentrations above the
permissible exposure level, in a range of 13-19 parts AN per million
parts of air (13-19 ppm).
F. Permissible exposure: Exposure may not exceed either:
1. Two parts AN per million parts of air (2 ppm) averaged over the
8-hour workday; or
2. Ten parts AN per million parts of air (10 ppm) averaged over any
15-minute period in the workday.
3. In addition, skin and eye contact with liquid AN is prohibited.
ii. Health Hazard Data
A. Acrylonitrile can affect your body if you inhale the vapor
(breathing), if it comes in contact with your eyes or skin, or if you
swallow it. It may enter your body through your skin.
[[Page 323]]
B. Effects of overexposure: 1. Short-term exposure: Acrylonitrile
can cause eye irritation, nausea, vomiting, headache, sneezing,
weakness, and light-headedness. At high concentrations, the effects of
exposure may go on to loss of consciousness and death. When
acrylonitrile is held in contact with the skin after being absorbed into
shoe leather or clothing, it may produce blisters following several
hours of no apparent effect. Unless the shoes or clothing are removed
immediately and the area washed, blistering will occur. Usually there is
no pain or inflammation associated with blister formation.
2. Long-term exposure: Acrylonitrile has been shown to cause cancer
in laboratory animals and has been associated with higher incidences of
cancer in humans. Repeated or prolonged exposure of the skin to
acrylonitrile may produce irritation and dermatitis.
3. Reporting signs and symptoms: You should inform your employer if
you develop any signs or symptoms and suspect they are caused by
exposure to acrylonitrile.
iii. Emergency First Aid Procedures
A. Eye exposure: If acrylonitrile gets into your eyes, wash your
eyes immediately with large amounts of water, lifting the lower and
upper lids occasionally. Get medical attention immediately. Contact
lenses should not be worn when working with this chemical.
B. Skin exposure: If acrylonitrile gets on your skin, immediately
wash the contaminated skin with water. If acrylonitrile soaks through
your clothing, especially your shoes, remove the clothing immediately
and wash the skin with water. If symptoms occur after washing, get
medical attention immediately. Thoroughly wash the clothing before
reusing. Contaminated leather shoes or other leather articles should be
discarded.
C. Inhalation: If you or any other person breathes in large amounts
of acrylonitrile, move the exposed person to fresh air at once. If
breathing has stopped, perform artificial respiration. Keep the affected
person warm and at rest. Get medical attention as soon as possible.
D. Swallowing: When acrylonitrile has been swallowed, give the
person large quantities of water immediately. After the water has been
swallowed, try to get the person to vomit by having him touch the back
of his throat with his finger. Do not make an unconscious person vomit.
Get medical attention immediately.
E. Rescue: Move the affected person from the hazardous exposure. If
the exposed person has been overcome, notify someone else and put into
effect the established emergency procedures. Do not become a casualty
yourself. Understand your emergency rescue procedures and know the
location of the emergency equipment before the need arises.
F. Special first aid procedures: First aid kits containing an
adequate supply (at least two dozen) of amyl nitrite pearls, each
containing 0.3 ml, should be maintained at each site where acrylonitrile
is used. When a person is suspected of receiving an overexposure to
acrylonitrile, immediately remove that person from the contaminated area
using established rescue procedures. Contaminated clothing must be
removed and the acrylonitrile washed from the skin immediately.
Artificial respiration should be started at once if breathing has
stopped. If the person is unconscious, amyl nitrite may be used as an
antidote by a properly trained individual in accordance with established
emergency procedures. Medical aid should be obtained immediately.
iv. Respirators and Protective Clothing
A. Respirators. You may be required to wear a respirator for
nonroutine activities, in emergencies, while your employer is in the
process of reducing acrylonitrile exposures through engineering
controls, and in areas where engineering controls are not feasible. If
respirators are worn, they must have a label issued by the National
Institute for Occupational Safety and Health under the provisions of 42
CFR part 84 stating that the respirators have been approved for use with
organic vapors. For effective protection, respirators must fit your face
and head snugly. Respirators must not be loosened or removed in work
situations where their use is required.
Acrylonitrile does not have a detectable odor except at levels above
the permissible exposure limits. Do not depend on odor to warn you when
a respirator cartridge or canister is exhausted. Cartridges or canisters
must be changed daily or before the end-of-service-life, whichever comes
first. Reuse of these may allow acrylonitrille to gradually filter
through the cartridge and cause exposures which you cannot detect by
odor. If you can smell acrylonitrile while wearing a respirator, proceed
immediately to fresh air. If you experience difficulty breathing while
wearing a respirator, tell your employer.
B. Supplied-air suits: In some work situations, the wearing of
supplied-air suits may be necessary. Your employer must instruct you in
their proper use and operation.
C. Protective clothing: You must wear impervious clothing, gloves,
face shield, or other appropriate protective clothing to prevent skin
contact with liquid acrylonitrile. Where protective clothing is
required, your employer is required to provide clean garments to you as
necessary to assume that the clothing protects you adequately.
Replace or repair impervious clothing that has developed leaks.
Acrylonitrile should never be allowed to remain on the skin.
Clothing and shoes which are not impervious to acrylonitrile
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should not be allowed to become contaminated with acrylonitrile, and if
they do the clothing and shoes should be promptly removed and
decontaminated. The clothing should be laundered or discarded after the
AN is removed. Once acrylonitrile penetrates shoes or other leather
articles, they should not be worn again.
D. Eye protection: You must wear splashproof safety goggles in areas
where liquid acrylonitrile may contact your eyes. In addition, contact
lenses should not be worn in areas where eye contact with acrylonitrile
can occur.
v. Precautions for Safe Use, Handling, and Storage
A. Acrylonitrile is a flammable liquid, and its vapors can easily
form explosive mixtures in air.
B. Acrylonitrile must be stored in tightly closed containers in a
cool, well-ventilated area, away from heat, sparks, flames, strong
oxidizers (especially bromine), strong bases, copper, copper alloys,
ammonia, and amines.
C. Sources of ignition such as smoking and open flames are
prohibited wherever acrylonitrile is handled, used, or stored in a
manner that could create a potential fire or explosion hazard.
D. You should use non-sparking tools when opening or closing metal
containers of acrylonitrile, and containers must be bonded and grounded
when pouring or transferring liquid acrylonitrile.
E. You must immediately remove any non-impervious clothing that
becomes wetted with acrylonitrile, and this clothing must not be reworn
until the acrylonitrile is removed from the clothing.
F. Impervious clothing wet with liquid acrylonitrile can be easily
ignited. This clothing must be washed down with water before you remove
it.
G. If your skin becomes wet with liquid acrylonitrile, you must
promptly and thoroughly wash or shower with soap or mild detergent to
remove any acrylonitrile from your skin.
H. You must not keep food, beverages, or smoking materials, nor are
you permitted to eat or smoke in regulated areas where acrylonitrile
concentrations are above the permissible exposure limits.
I. If you contact liquid acrylonitrile, you must wash your hands
thoroughly with soap or mild detergent and water before eating, smoking,
or using toilet facilities.
J. Fire extinguishers and quick drenching facilities must be readily
available, and you should know where they are and how to operate them.
K. Ask your supervisor where acrylonitrile is used in your work area
and for any additional plant safety and health rules.
vi. Access to Information
A. Each year, your employer is required to inform you of the
information contained in this Substance Safety Data Sheet for
acrylonitrile. In addition, you employer must instruct you in the proper
work practices for using acrylonitrile, emergency procedures, and the
correct use of protective equipment.
B. Your employer is required to determine whether you are being
exposed to acrylonitrile. 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.
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 forty (40) years or for the period of your employment plus twenty
(20) years, whichever is longer.
D. Your employer is required to release your exposure and medical
records to you or your representative upon your request.
Appendix B to Sec. 1910.1045--Substance Technical Guidelines for
Acrylonitrile
i. Physical and Chemical Data
A. Substance identification: 1. Synonyms: AN; VCN; vinyl cyanide;
propenenitrile; cyanoethylene; Acrylon; Carbacryl; Fumigrain; Ventox.
2. Formula: CH2=CHCN.
3. Molecular weight: 53.1.
B. Physical data: 1. Boiling point (760 mm Hg): 77.3 deg.C (171
deg.F);
2. Specific gravity (water=1): 0.81 (at 20 deg.C or 68 deg.F);
3. Vapor density (air=1 at boiling point of acrylonitrile): 1.83;
4. Melting point: -83 deg.C (-117 deg.F);
5. Vapor pressure (@20 deg.F): 83 mm Hg;
6. Solubility in water, percent by weight @20 deg.C (68 deg.F):
7.35;
7. Evaporation rate (Butyl Acetate=1): 4.54; and
8. Appearance and odor: Colorless to pale yellow liquid with a
pungent odor at concentrations above the permissible exposure level. Any
detectable odor of acrylonitrile may indicate overexposure.
ii. Fire, Explosion, and Reactivity Hazard Data
A. Fire: 1. Flash point: -1 deg.C (30 deg.F) (closed cup).
2. Autoignition temperature: 481 deg.C (898 deg.F).
3. Flammable limits air, percent by volume: Lower: 3, Upper: 17.
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4. Extinguishing media: Alcohol foam, carbon dioxide, and dry
chemical.
5. Special fire-fighting procedures: Do not use a solid stream of
water, since the stream will scatter and spread the fire. Use water to
cool containers exposed to a fire.
6. Unusual fire and explosion hazards: Acrylonitrile is a flammable
liquid. Its vapors can easily form explosive mixtures with air. All
ignition sources must be controlled where acrylonitrile is handled,
used, or stored in a manner that could create a potential fire or
explosion hazard. Acrylonitrile vapors are heavier than air and may
travel along the ground and be ignited by open flames or sparks at
locations remote from the site at which acrylonitrile is being handled.
7. For purposes of compliance with the requirements of 29 CFR
1910.106, acrylonitrile is classified as a class IB flammable liquid.
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 1910.157, acrylonitrile is
classified as a Class B fire hazard.
9. For purpose of compliance with 29 CFR 1919.309, locations
classified as hazardous due to the presence of acrylonitrile shall be
Class I, Group D.
B. Reactivity:
1. Conditions contributing to instability: Acrylonitrile will
polymerize when hot, and the additional heat liberated by the
polymerization may cause containers to explode. Pure AN may self-
polymerize, with a rapid build-up of pressure, resulting in an explosion
hazard. Inhibitors are added to the commercial product to prevent self-
polymerization.
2. Incompatibilities: Contact with strong oxidizers (especially
bromine) and strong bases may cause fires and explosions. Contact with
copper, copper alloys, ammonia, and amines may start serious
decomposition.
3. Hazardous decompostion products: Toxic gases and vapors (such as
hydrogen cyanide, oxides of nitrogen, and carbon monoxide) may be
released in a fire involving acrylonitrile and certain polymers made
from acrylonitrile.
4. Special precautions: Liquid acrylonitrile will attack some forms
of plastics, rubbers, and coatings.
iii. Spill, Leak, and Disposal Procedures
A. If acrylonitrile is spilled or leaked, the following steps should
be taken:
1. Remove all ignition sources.
2. The area should be evacuated at once and re-entered only after
the area has been thoroughly ventilated and washed down with water.
3. If liquid acrylonitrile or polymer intermediate, collect for
reclamation or absorb in paper, vermiculite, dry sand, earth, or similar
material, or wash down with water into process sewer system.
B. Persons not wearing protective equipment should be restricted
from areas of spills or leaks until clean-up has been completed.
C. Waste disposal methods: Waste material shall be disposed of in a
manner that is not hazardous to employees or to the general population.
Spills of acrylonitrile and flushing of such spills shall be channeled
for appropriate treatment or collection for disposal. They shall not be
channeled directly into the sanitary sewer system. In selecting the
method of waste disposal, applicable local, State, and Federal
regulations should be consulted.
iv. Monitoring and Measurement Procedures
A. Exposure above the Permissible Exposure Limit:
1. Eight-hour exposure evaluation: Measurements taken for the
purpose of determining employee exposure under this section are best
taken so that the average 8-hour exposure may be determined from a
single 8-hour sample or two (2) 4-hour samples. Air samples should be
taken in the employee's breathing zone (air that would most nearly
represent that inhaled by the employee.)
2. Ceiling evaluation: Measurements taken for the purpose of
determining employee exposure under this section must be taken during
periods of maximum expected airborne concentrations of acrylonitrile in
the employee's breathing zone. A minimum of three (3) measurements
should be taken on one work shift. The average of all measurements taken
is an estimate of the employee's ceiling exposure.
3. Monitoring techniques: The sampling and analysis under this
section may be performed by collecting the acrylonitrile vapor on
charcoal adsorption tubes or other composition adsorption tubes, with
subsequent chemical analysis. Sampling and analysis may also be
performed by instruments such as real-time continuous monitoring
systems, portable direct-reading instruments, or passive dosimeters.
Analysis of resultant samples should be by gas chromatograph.
Appendix D lists methods of sampling and analysis which have been
tested by NIOSH and OSHA for use with acrylonitrile. NIOSH and OSHA have
validated modifications of NIOSH Method S-156 (See Appendix D) under
laboratory conditions for concentrations below 1 ppm. The employer has
the obligation of selecting a monitoring method which meets the accuracy
and precision requirements of the standard under his unique field
conditions. The standard requires that methods of monitoring must be
accurate, to a 95-percent confidence level, to 35-percent
for concentrations of AN at or above 2 ppm, and to 50-
percent for concentrations below 2
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ppm. In addition to the methods described in Appendix D, there are
numerous other methods available for monitoring for AN in the workplace.
Details on these other methods have been submitted by various companies
to the rulemaking record, and are available at the OSHA Docket Office.
B. Since many of the duties relating to employee exposure are
dependent on the results of monitoring and measuring procedures,
employers shall assure that the evaluation of employee exposures is
performed by a competent industrial hygienist or other technically
qualified person.
v. Protective Clothing
Employees shall be provided with and required to wear appropriate
protective clothing to prevent any possibility of skin contact with
liquid AN. Because acrylonitrile is absorbed through the skin, it is
important to prevent skin contact with liquid AN. Protective clothing
shall include impermeable coveralls or similar full-body work clothing,
gloves, head-coverings, as appropriate to protect areas of the body
which may come in contact with liquid AN.
Employers should ascertain that the protective garmets are
impermeable to acrylonitrile. Non-impermeable clothing and shoes should
not be allowed to become contaminated with liquid AN. If permeable
clothing does become contaminated, it should be promptly removed, placed
in a regulated area for removal of the AN, and not worn again until the
AN is removed. If leather footwear or other leather garments become wet
from acrylonitrile, they should be replaced and not worn again, due to
the ability of leather to absorb acrylonitrile and hold it against the
skin. Since there is no pain associated with the blistering which may
result from skin contact with liquid AN, it is essential that the
employee be informed of this hazard so that he or she can be protected.
Any protective clothing which has developed leaks or is otherwise
found to be defective shall be repaired or replaced. Clean protective
clothing shall be provided to the employee as necessary to assure its
protectiveness. Whenever impervious clothing becomes wet with liquid AN,
it shall be washed down with water before being removed by the employee.
Employees are also required to wear splash-proof safety goggles where
there is any possibility of acrylonitrile contacting 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. The employer is required to institute a leak and spill
detection program for operations involving liquid AN in order to detect
sources of fugitive AN emissions.
B. Dry sweeping and the use of compressed air is unsafe for the
cleaning of floors and other surfaces where liquid AN may be found.
C. Adequate washing facilities with hot and cold water are to be
provided, and maintained in a sanitary condition. Suitable cleansing
agents are also to be provided to assure the effective removal of
acrylonitrile from the skin.
D. Change or dressing rooms with individual clothes storage
facilities must be provided to prevent the contamination of street
clothes with acrylonitrile. Because of the hazardous nature of
acrylonitrile, contaminated protective clothing should be placed in a
regulated area designated by the employer for removal of the AN before
the clothing is laundered or disposed of.
vii. Miscellaneous Precautions
A. Store acrylonitrile in tightly-closed containers in a cool, well-
ventilated area and take necessary precautions to avoid any explosion
hazard.
B. High exposures to acrylonitrile can occur when transferring the
liquid from one container to another.
C. Non-sparking tools must be used to open and close metal
acrylonitrile containers. These containers must be effectively grounded
and bonded prior to pouring.
D. Never store uninhibited acrylonitrile.
E. Acrylonitrile vapors are not inhibited. They may form polymers
and clog vents of storage tanks.
F. Use of supplied-air suits or other impervious coverings may be
necessary to prevent skin contact with and provide respiratory
protection from acrylonitrile where the concentration of acrylonitrile
is unknown or is above the ceiling limit. Supplied-air suits should be
selected, used, and maintained under the immediate supervision of
persons knowledgeable in the limitations and potential life-endangering
characteristics of supplied-air suits.
G. Employers shall advise employees of all areas and operations
where exposure to acrylonitrile could occur.
viii. Common Operations
Common operations in which exposure to acrylonitrile is likely to
occur include the following: Manufacture of the acrylonitrile monomer;
synthesis of acrylic fibers, ABS, SAN, and nitrile barrier plastics and
resins, nitrile rubber, surface coatings, specialty chemicals, use as a
chemical intermediate, use as a fumigant and in the cyanoethylation of
cotton.
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Appendix C to Sec. 1910.1045--Medical Surveillance Guidelines for
Acrylonitrile
i. route of entry
Inhalation; skin absorption; ingestion.
ii. toxicology
Acrylonitrile vapor is an asphyxiant due to inhibitory action on
metabolic enzyme systems. Animals exposed to 75 or 100 ppm for 7 hours
have shown signs of anoxia; in some animals which died at the higher
level, cyanomethemoglobin was found in the blood. Two human fatalities
from accidental poisioning have been reported; one was caused by
inhalation of an unknown concentration of the vapor, and the other was
thought to be caused by skin absorption or inhalation. Most cases of
intoxication from industrial exposure have been mild, with rapid onset
of eye irritation, headache, sneezing, and nausea. Weakness,
lightheadedness, and vomiting may also occur. Exposure to high
concentrations may produce profound weakness, asphyxia, and death. The
vapor is a severe eye irritant. Prolonged skin contract with the liquid
may result in absorption with systemic effects, and in the formation of
large blisters after a latent period of several hours. Although there is
usually little or no pain or inflammation, the affected skin resembles a
second-degree thermal burn. Solutions spilled on exposed skin, or on
areas covered only by a light layer of clothing, evaporate rapidly,
leaving no irritation, or, at the most, mild transient redness. Repeated
spills on exposed skin may result in dermatitis due to solvent effects.
Results after 1 year of a planned 2-year animal study on the effects
of exposure to acrylonitrile have indicated that rats ingesting as
little as 35 ppm in their drinking water develop tumors of the central
nervous system. The interim results of this study have been supported by
a similar study being conducted by the same laboratory, involving
exposure of rats by inhalation of acrylonitrile vapor, which has shown
similar types of tumors in animals exposed to 80 ppm.
In addition, the preliminary results of an epidemiological study
being performed by duPont on a cohort of workers in their Camden, S.C.
acrylic fiber plant indicate a statistically significant increase in the
incidence of colon and lung cancers among employees exposed to
acrylonitrile.
iii. signs and symptoms of acute overexposure
Asphyxia and death can occur from exposure to high concentrations of
acrylonitrile. Symptoms of overexposure include eye irritation,
headache, sneezing, nausea and vomiting, weakness, and light-headedness.
Prolonged skin contact can cause blisters on the skin with appearance of
a second-degree burn, but with little or no pain. Repeated skin contact
may produce scaling dermatits.
iv. treatment of acute overexposure
Remove employee from exposure. Immediately flush eyes with water and
wash skin with soap or mild detergent and water. If AN has been
swallowed, and person is conscious, induce vomiting. Give artificial
resuscitation if indicated. More severe cases, such as those associated
with loss of consciousness, may be treated by the intravenous
administration of sodium nitrite, followed by sodium thiosulfate,
although this is not as effective for acrylonitrile poisoning as for
inorganic cyanide poisoning.
v. surveillance and preventive considerations
A. As noted above, exposure to acrylonitrile has been linked to
increased incidence of cancers of the colon and lung in employees of the
duPont acrylic fiber plant in Camden, S.C. In addition, the animal
testing of acrylonitrile has resulted in the development of cancers of
the central nervous system in rats exposed by either inhalation or
ingestion. The physician should be aware of the findings of these
studies in evaluating the health of employees exposed to acrylonitrile.
Most reported acute effects of occupational exposure to
acrylonitrile are due to its ability to cause tissue anoxia and
asphyxia. The effects are similar to those caused by hydrogen cyanide.
Liquid acrylonitrile can be absorbed through the skin upon prolonged
contact. The liquid readily penetrates leather, and will produce burns
of the feet if footwear contaminated with acrylonitrile is not removed.
It is important for the physician to become familiar with the
operating conditions in which exposure to acrylonitrile may occur. Those
employees with skin diseases may not tolerate the wearing of whatever
protective clothing may be necessary to protect them from exposure. In
addition, those with chronic respiratory disease may not tolerate the
wearing of negative-pressure respirators.
B. Surveillance and screening. Medical histories and laboratory
examinations are required for each employee subject to exposure to
acrylonitrile above the action level. The employer must screen employees
for history of certain medical conditions which might place the employee
at increased risk from exposure.
1. Central nervous system dysfunction. Acute effects of exposure to
acrylonitrile generally involve the central nervous system. Symptoms of
acrylonitrile exposure include headache, nausea, dizziness, and general
weakness. The animal studies cited above suggest possible carcinogenic
effects of acrylonitrile
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on the central nervous system, since rats exposed by either inhalation
or ingestion have developed similar CNS tumors.
2. Respiratory disease. The du Pont data indicate an increased risk
of lung cancer among employees exposed to acrylonitrile.
3. Gastrointestinal disease. The du Pont data indicate an increased
risk of cancer of the colon among employees exposed to acrylonitrile. In
addition, the animal studies show possible tumor production in the
stomachs of the rats in the ingestion study.
4. Skin disease. Acrylonitrile can cause skin burns when prolonged
skin contact with the liquid occurs. In addition, repeated skin contact
with the liquid can cause dermatitis.
5. General. The purpose of the medical procedures outlined in the
standard is to establish a baseline for future health monitoring.
Persons unusually susceptible to the effects of anoxia or those with
anemia would be expected to be at increased risk. In addition to
emphasis on the CNS, respiratory and gastro-intestinal systems, the
cardiovascular system, liver, and kidney function should also be
stressed.
Appendix D to Sec. 1910.1045--Sampling and Analytical Methods for
Acrylonitrile
There are many methods available for monitoring employee exposures
to acrylonitrile. Most of these involve the use of charcoal tubes and
sampling pumps, with analysis by gas chromatograph. The essential
differences between the charcoal tube methods include, among others, the
use of different desorbing solvents, the use of different lots of
charcoal, and the use of different equipment for analysis of the
samples.
Besides charcoal, considerable work has been performed on methods
using porous polymer sampling tubes and passive dosimeters. In addition,
there are several portable gas analyzers and monitoring units available
on the open market.
This appendix contains details for the methods which have been
tested at OSHA Analytical Laboratory in Salt Lake City, and NIOSH in
Cincinnati. Each is a variation on NIOSH Method S-156, which is also
included for reference. This does not indicate that these methods are
the only ones which will be satisfactory. There also may be workplace
situations in which these methods are not adequate, due to such factors
as high humidity. Copies of the other methods available to OSHA are
available in the rulemaking record, and may be obtained from the OSHA
Docket Office. These include, the Union Carbide, Monsanto, Dow Chemical
and Dow Badische methods, as well as NISOH Method P & CAM 127.
Employers who note problems with sample breakthrough should try
larger charcoal tubes. Tubes of larger capacity are available, and are
often used for sampling vinyl chloride. In addition, lower flow rates
and shorter sampling times should be beneficial in minimizing
breakthrough problems.
Whatever method the employer chooses, he must assure himself of the
method's accuracy and precision under the unique conditions present in
his workplace.
NIOSH Method S-156 (Unmodified)
Analyte: Acrylonitrile.
Matrix: Air.
Procedure: Absorption on charcoal, desorption with methanol, GC.
1. Principle of the method (Reference 11.1).
1.1 A known volume of air is drawn through a charcoal tube to trap
the organic vapors present.
1.2 The charcoal in the tube is transferred to a small, stoppered
sample container, and the analyte is desorbed with methanol.
1.3 An aliquot of the desorbed sample is injected into a gas
chromatograph.
1.4 The area of the resulting peak is determined and compared with
areas obtained for standards.
2. Range and sensitivity.
2.1 This method was validated over the range of 17.5-70.0 mg/cu m at
an atmospheric temperature and pressure of 22 deg.C and 760 MM Hg,
using a 20-liter sample. Under the conditions of sample size (20-liters)
the probable useful range of this method is 4.5-135 mg-cu m. The method
is capable of measuring much smaller amounts if the desorption
efficiency is adequate. Desorption efficiency must be determined over
the range used.
2.2 The upper limit of the range of the method is dependent on the
adsorptive capacity of the charcoal tube. This capacity varies with the
concentrations of acrylonitrile and other substances in the air. The
first section of the charcoal tube was found to hold at least 3.97 mg of
acrylonitrile when a test atmosphere containing 92.0 mg/cu m of
acrylonitrile in air was sampled 0.18 liter per minute for 240 minutes;
at that time the concentration of acrylonitrile in the effluent was less
than 5 percent of that in the influent. (The charcoal tube consists of
two sections of activated charcoal separated by a section of urethane
foam. See section 6.2.) If a particular atmosphere is suspected of
containing a large amount of contaminant, a smaller sampling volume
should be taken.
3. Interference.
3.1 When the amount of water in the air is so great that
condensation actually occurs in the tube, organic vapors will not be
trapped efficiently. Preliminary experiments using toluene indicate that
high humidity severely decreases the breakthrough volume.
3.2 When interfering compounds are known or suspected to be present
in the air, such information, including their suspected identities,
should be transmitted with the sample.
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3.3 It must be emphasized that any compound which has the same
retention time as the analyte at the operating conditions described in
this method is an interference. Retention time data on a single column
cannot be considered proof of chemical identity.
3.4 If the possibility of interference exists, separation
conditions (column packing, temperature, etc.) must be changed to
circumvent the problem.
4. Precision and accuracy.
4.1 The Coefficient of Variation (CVT) for the total
analytical and sampling method in the range of 17.5-70.0 mg/cu m was
0.073. This value corresponds to a 3.3 mg/cu m standard deviation at the
(previous) OSHA standard level (20 ppm). Statistical information and
details of the validation and experimental test procedures can be found
in Reference 11.2.
4.2 On the average the concentrations obtained at the 20 ppm level
using the overall sampling and analytical method were 6.0 percent lower
than the ``true'' concentrations for a limited number of laboratory
experiments. Any difference between the ``found'' and ``true''
concentrations may not represent a bias in the sampling and analytical
method, but rather a random variation from the experimentally determined
``true'' concentration. Therefore, no recovery correction should be
applied to the final result in section 10.5.
5. Advantages and disadvantages of the method.
5.1 The sampling device is small, portable, and involves no
liquids. Interferences are minimal, and most of those which do occur can
be eliminated by altering chromatographic conditions. The tubes are
analyzed by means of a quick, instrumental method.
The method can also be used for the simultaneous analysis of two or
more substances suspected to be present in the same sample by simply
changing gas chromatographic conditions.
5.2 One disadvantage of the method is that the amount of sample
which can be taken is limited by the number of milligrams that the tube
will hold before overloading. When the sample value obtained for the
backup section of the charcoal tube exceeds 25 percent of that found on
the front section, the possibility of sample loss exists.
5.3 Furthermore, the precision of the method is limited by the
reproducibility of the pressure drop across the tubes. This drop will
affect the flow rate and cause the volume to be imprecise, because the
pump is usually calibrated for one tube only.
6. Apparatus.
6.1 A calibrated personal sampling pump whose flow can be
determined within 5 percent at the recommended flow rate.
(Reference 11.3).
6.2 Charcoal tubes: Glass tubes with both ends flame sealed, 7 cm
long with a 6-mm O.D. and a 4-mm I.D., containing 2 sections of 20/40
mesh activated charcoal separated by a 2-mm portion of urethane foam.
The activated charcoals prepared from coconut shells and is fired at 600
deg.C prior to packing. The adsorbing section contains 100 mg of
charcoal, the backup section 50 mg. A 3-mm portion of urethane foam is
placed between the outlet end of the tube and the backup section. A plug
of silicated glass wool is placed in front of the adsorbing section. The
pressure drop across the tube must be less than 1 inch of mercury at a
flow rate of 1 liter per minute.
6.3 Gas chromatograph equipped with a flame ionization detector.
6.4 Column (4-ftx\1/4\-in stainless steel) packed with 50/80 mesh
Poropak, type Q.
6.5 An electronic integrator or some other suitable method for
measuring peak areas.
6.6 Two-milliliter sample containers with glass stoppers or Teflon-
lined caps. If an automatic sample injector is used, the associated
vials may be used.
6.7 Microliter syringes: 10-microliter and other convenient sizes
for making standards.
6.8 Pipets: 1.0-ml delivery pipets.
6.9 Volumetric flask: 10-ml or convenient sizes for making standard
solutions.
7. Reagents.
7.1 Chromatographic quality methanol.
7.2 Acrylonitrile, reagent grade.
7.3 Hexane, reagent grade.
7.4 Purified nitrogen.
7.5 Prepurified hydrogen.
7.6 Filtered compressed air.
8. Procedure.
8.1 Cleaning of equipment. All glassware used for the laboratory
analysis should be detergent washed and thoroughly rinsed with tap water
and distilled water.
8.2 Calibration of personal pumps. Each personal pump must be
calibrated with a representative charcoal tube in the line. This will
minimize errors associated with uncertainties in the sample volume
collected.
8.3 Collection and shipping of samples.
8.3.1 Immediately before sampling, break the ends of the tube to
provide an opening at least one-half the internal diameter of the tube
(2 mm).
8.3.2 The smaller section of charcoal is used as a backup and
should be positioned nearest the sampling pump.
8.3.3 The charcoal tube should be placed in a vertical direction
during sampling to minimize channeling through the charcoal.
8.3.4 Air being sampled should not be passed through any hose or
tubing before entering the charcoal tube.
8.3.5 A maximum sample size of 20 liters is recommended. Sample at
a flow of 0.20 liter per minute or less. The flow rate should be known
with an accuracy of at least 5 percent.
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8.3.6 The temperature and pressure of the atmosphere being sampled
should be recorded. If pressure reading is not available, record the
elevation.
8.3.7 The charcoal tubes should be capped with the supplied plastic
caps immediately after sampling. Under no circumstances should rubber
caps be used.
8.3.8 With each batch of 10 samples submit one tube from the same
lot of tubes which was used for sample collection and which is subjected
to exactly the same handling as the samples except that no air is drawn
through it. Label this as a blank.
8.3.9 Capped tubes should be packed tightly and padded before they
are shipped to minimize tube breakage during shipping.
8.3.10 A sample of the bulk material should be submitted to the
laboratory in a glass container with a Teflon-lined cap. This sample
should not be transported in the same container as the charcoal tubes.
8.4 Analysis of samples.
8.4.1 Preparation of samples. In preparation for analysis, each
charcoal tube is scored with a file in front of the first section of
charcoal and broken open. The glass wool is removed and discarded. The
charcoal in the first (larger) section is transferred to a 2-ml
stoppered sample container. The separating section of foam is removed
and discarded; the second section is transferred to another stoppered
container. These two sections are analyzed separately.
8.4.2 Desorption of samples. Prior to analysis, 1.0 ml of methanol
is pipetted into each sample container. Desorption should be done for 30
minutes. Tests indicate that this is adequate if the sample is agitated
occasionally during this period. If an automatic sample injector is
used, the sample vials should be capped as soon as the solvent is added
to minimize volatilization.
8.4.3 GC conditions. The typical operating conditions for the gas
chromatograph are:
1. 50 ml/min (60 psig) nitrogen carrier gas flow.
2. 65 ml/min (24 psig) hydrogen gas flow to detector.
3. 500 ml/min (50 psig) air flow to detector.
4. 235 deg.C injector temperature.
5. 255 deg.C manifold temperature (detector).
6. 155 deg.C column temperature.
8.4.4 Injection. The first step in the analysis is the injection of
the sample into the gas chromatograph. To eliminate difficulties arising
from blowback or distillation within the syringe needle, one should
employ the solvent flush injection technique. The 10-microliter syringe
is first flushed with solvent several times to wet the barrel and
plunger. Three microliters of solvent are drawn into the syringe to
increase the accuracy and reproducibility of the injected sample volume.
The needle is removed from the solvent, and the plunger is pulled back
about 0.2 microliter to separate the solvent flush from the sample with
a pocket of air to be used as a marker. The needle is then immersed in
the sample, and a 5-microliter aliquot is withdrawn, taking into
consideration the volume of the needle, since the sample in the needle
will be completely injected. After the needle is removed from the sample
and prior to injection, the plunger is pulled back 1.2 microliters to
minimize evaporation of the sample from the tip of the needle. Observe
that the sample occupies 4.9-5.0 microliters in the barrel of the
syringe. Duplicate injections of each sample and standard should be
made. No more than a 3 percent difference in area is to be expected. An
automatic sample injector can be used if it is shown to give
reproducibility at least as good as the solvent flush method.
8.4.5 Measurement of area. The area of the sample peak is measured
by an electronic integrator or some other suitable form of area
measurement, and preliminary results are read from a standard curve
prepared as discussed below.
8.5 Determination of desorption efficiency.
8.5.1 Importance of determination. The desorption efficiency of a
particular compound can vary from one laboratory to another and also
from one batch of charcoal to another. Thus, it is necessary to
determine at least once the percentage of the specific compound that is
removed in the desorption process, provided the same batch of charcoal
is used.
8.5.2 Procedure for determining desorption efficiency. Activated
charcoal equivalent to the amount in the first section of the sampling
tube (100 mg) is measured into a 2.5 in, 4-mm I.D. glass tube, flame
sealed at one end. This charcoal must be from the same batch as that
used in obtaining the samples and can be obtained from unused charcoal
tubes. The open end is capped with Parafilm. A known amount of hexane
solution of acrylonitrile containing 0.239 g/ml is injected directly
into the activated charcoal with a microliter syringe, and tube is
capped with more Parafilm. When using an automatic sample injector, the
sample injector vials, capped with Teflon-faced septa, may be used in
place of the glass tube.
The amount injected is equivalent to that present in a 20-liter air
sample at the selected level.
Six tubes at each of three levels (0.5X, 1X, and 2X of the standard)
are prepared in this manner and allowed to stand for at least overnight
to assure complete adsorption of the analyte onto the charcoal. These
tubes are referred to as the sample. A parallel blank tube should be
treated in the same manner except that no sample is added to it. The
sample and blank tubes are desorbed and analyzed in exactly the same
manner as the sampling tube described in section 8.4.
Two or three standards are prepared by injecting the same volume of
compound into
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1.0 ml of methanol with the same syringe used in the preparation of the
samples. These are analyzed with the samples.
The desorption efficiency (D.E.) equals the average weight in mg
recovered from the tube divided by the weight in mg added to the tube,
or
[GRAPHIC] [TIFF OMITTED] TC15NO91.035
The desorption efficiency is dependent on the amount of analyte
collected on the charcoal. Plot the desorption efficiency versus weight
of analyte found. This curve is used in section 10.4 to correct for
adsorption losses.
9. Calibration and standards.
It is convenient to express concentration of standards in terms of
mg/1.0 ml methanol, because samples are desorbed in this amount of
methanol. The density of the analyte is used to convert mg into
microliters for easy measurement with a microliter syringe. A series of
standards, varying in concentration over the range of interest, is
prepared and analyzed under the same GC conditions and during the same
time period as the unknown samples. Curves are established by plotting
concentration in mg/1.0 ml versus peak area.
Note: Since no internal standard is used in the method, standard
solutions must be analyzed at the same time that the sample analysis is
done. This will minimize the effect of known day-to-day variations and
variations during the same day of the FID response.
10. Calculations.
10.1 Read the weight, in mg, corresponding to each peak area from
the standard curve. No volume corrections are needed, because the
standard curve is based on mg/1.0 ml methanol and the volume of sample
injected is identical to the volume of the standards injected.
10.2 Corrections for the bank must be made for each sample.
mg = mg sample-mg blank
Where:
mg sample = mg found in front section of sample tube.
mg sample = mg found in front section of blank tube.
A similar procedure is followed for the backup sections.
10.3 Add the weights found in the front and backup sections to get
the total weight in the sample.
10.4 Read the desorption efficiency from the curve (see sec. 8.5.2)
for the amount found in the front section. Divide the total weight by
this desorption efficiency to obtain the corrected mg/sample.
[GRAPHIC] [TIFF OMITTED] TC15NO91.036
10.5 The concentration of the analyte in the air sampled can be
expressed in mg/cu m.
[GRAPHIC] [TIFF OMITTED] TC15NO91.037
10.6 Another method of expressing concentration is ppm.
ppm =m mg/cu x 24.45/M.W. x 760/Px T. + 273/298
Where:
P = Pressure (mm Hg) of air sampled.
T = Temperature ( deg.C) of air sampled.
24.45 = Molar volume (liter/mole) at 25 deg.C and 760 mm Hg.
M.W. = Molecular weight (g/mole) of analyte.
760 = Standard pressure (mm Hg).
298 = Standard temperature ( deg.K).
11. References.
11.1 White, L. D. et al., ``A Convenient Optimized Method for the
Analysis of Selected Solvent Vapors in the Industrial Atmosphere,''
Amer. Ind. Hyg. Assoc. J., 31:225 (1970).
11.2 Documentation of NIOSH Validation Tests, NIOSH Contract No.
CDC-99-74-45.
11.3 Final Report, NIOSH Contract HSM-99-71-31, ``Personal Sampler
Pump for Charcoal Tubes,'' September 15, 1972.
NIOSH Modification of NIOSH Method S-156
The NIOSH recommended method for low levels for acrylonitrile is a
modification of method S-156. It differs in the following respects:
(1) Samples are desorbed using 1 ml of 1 percent acetone in
CS2 rather than methanol.
(2) The analytical column and conditions are:
Column: 20 percent SP-1000 on 80/100 Supelcoport 10 feet x \1/8\
inch S.S.
Conditions:
Injector temperature: 200 deg.C.
Detector temperature: 100 deg.C.
Column temperature: 85 deg.C.
Helium flow: 25 ml/min.
Air flow: 450 ml/min.
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Hydrogen flow: 55 ml/min.
(3) A 2 [mu]l injection of the desorbed analyte is used.
(4) A sampling rate of 100 ml/min is recommended.
OSHA Laboratory Modification of NIOSH Method S-156
Analyte: Acrylonitrile.
Matrix: Air.
Procedure: Adsorption on charcoal, desorption with methanol, GC.
1. Principle of the Method (Reference 1).
1.1 A known volume of air is drawn through a charcoal tube to trap
the organic vapors present.
1.2 The charcoal in the tube is transferred to a small, stoppered
sample vial, and the analyte is desorbed with methanol.
1.3 An aliquot of the desorbed sample is injected into a gas
chromatograph.
1.4 The area of the resulting peak is determined and compared with
areas obtained for standards.
2. Advantages and disadvantages of the method.
2.1 The sampling device is small, portable, and involves no
liquids. Interferences are minimal, and most of those which do occur can
be eliminated by altering chromatographic conditions. The tubes are
analyzed by means of a quick, instrumental method.
2.2 This method may not be adequate for the simultaneous analysis
of two or more substances.
2.3 The amount of sample which can be taken is limited by the
number of milligrams that the tube will hold before overloading. When
the sample value obtained for the backup section of the charcoal tube
exceeds 25 percent of that found on the front section, the possibility
of sample loss exists.
2.4 The precision of the method is limited by the reproducibility
of the pressure drop across the tubes. This drop will affect the flow
rate and cause the volume to be imprecise, because the pump is usually
calibrated for one tube only.
3. Apparatus.
3.1 A calibrated personal sampling pump whose flow can be
determined within 5 percent at the recommended flow rate.
3.2 Charcoal tubes: Glass tube with both ends flame sealed, 7 cm
long with a 6-mm O.D. and a 4-mm I.D., containing 2 sections of 20/40
mesh activated charcoal separated by a 2-mm portion of urethane foam.
The activated charcoal is prepared from coconut shells and is fired at
600 deg.C prior to packing. The adsorbing section contains 100 mg of
charcoal, the back-up section 50 mg. A 3-mm portion of urethane foam is
placed between the outlet end of the tube and the back-up section. A
plug of sililated glass wool is placed in front of the adsorbing
section. The pressure drop across the tube must be less than one inch of
mercury at a flow rate of 1 liter per minute.
3.3 Gas chromatograph equipped with a nitrogen phosphorus detector.
3.4 Column (10-ft x 1/8-in stainless steel) packed with
100/120 Supelcoport coated with 10 percent SP 1000.
3.5 An electronic integrator or some other suitable method for
measuring peak area.
3.6 Two-milliliter sample vials with Teflon-lined caps
3.7 Microliter syringes: 10-microliter, and other convenient sizes
for making standards.
3.8 Pipets: 1.0-ml delivery pipets.
3.9 Volumetric flasks: convenient sizes for making standard
solutions.
4. Reagents.
4.1 Chromatographic quality methanol.
4.2 Acrylonitrile, reagent grade.
4.3 Filtered compressed air.
4.4 Purified hydrogen.
4.5 Purified helium.
5. Procedure.
5.1 Cleaning of equipment. All glassware used for the laboratory
analysis should be properly cleaned and free of organics which could
interfere in the analysis.
5.2 Calibration of personal pumps. Each pump must be calibrated with
a representative charcoal tube in the line.
5.3 Collection and shipping of samples.
5.3.1 Immediately before sampling, break the ends of the tube to
provide an opening at least one-half the internal diameter of the tube
(2 mm).
5.3.2 The smaller section of the charcoal is used as the backup and
should be placed nearest the sampling pump.
5.3.3 The charcoal should be placed in a vertical position during
sampling to minimize channeling through the charcoal.
5.3.4 Air being sampled should not be passed through any hose or
tubing before entering the charcoal tube.
5.3.5 A sample size of 20 liters is recommended. Sample at a flow
rate of approximately 0.2 liters per minute. The flow rate should be
known with an accuracy of at least 5 percent.
5.3.6 The temperature and pressure of the atmosphere being sampled
should be recorded.
5.3.7 The charcoal tubes should be capped with the supplied plastic
caps immediately after sampling. Rubber caps should not be used.
5.3.8 Submit at least one blank tube (a charcoal tube subjected to
the same handling procedures, without having any air drawn through it)
with each set of samples.
5.3.9. Take necessary shipping and packing precautions to minimize
breakage of samples.
5.4 Analysis of samples.
5.4.1 Preparation of samples. In preparation for analysis, each
charcoal tube is
[[Page 333]]
scored with a file in front of the first section of charcoal and broken
open. The glass wool is removed and discarded. The charcoal in the first
(larger) section is transferred to a 2-ml vial. The separating section
of foam is removed and discarded; the section is transferred to another
capped vial. These two sections are analyzed separately.
5.4.2 Desorption of samples. Prior to analysis, 1.0 ml of methanol
is pipetted into each sample container. Desorption should be done for 30
minutes in an ultrasonic bath. The sample vials are recapped as soon as
the solvent is added.
5.4.3 GC conditions. The typical operating conditions for the gas
chromatograph are:
1. 30 ml/min (60 psig) helium carrier gas flow.
2. 3.0 ml/min (30 psig) hydrogen gas flow to detector.
3. 50 ml/min (60 psig) air flow to detector.
4. 200 deg.C injector temperature.
5. 200 deg.C dejector temperature.
6. 100 deg.C column temperature.
5.4.4 Injection. Solvent flush technique or equivalent.
5.4.5 Measurement of area. The area of the sample peak is measured
by an electronic integator or some other suitable form of area
measurement, and preliminary results are read from a standard curve
prepared as discussed below.
5.5 Determination of desorption efficiency.
5.5.1 Importance of determination. The desorption efficiency of a
particular compound can vary from one laboratory to another and also
from one batch of charcoal to another. Thus, it is necessary to
determine, at least once, the percentage of the specific compound that
is removed in the desorption process, provided the same batch of
charcoal is used.
5.5.2 Procedure for determining desorption efficiency. The reference
portion of the charcoal tube is removed. To the remaining portion,
amounts representing 0.5X, 1X, and 2X (X represents TLV) based on a 20 l
air sample are injected onto several tubes at each level. Dilutions of
acrylonitrile with methanol are made to allow injection of measurable
quantities. These tubes are then allowed to equilibrate at least
overnight. Following equilibration they are analyzed following the same
procedure as the samples A curve of the desorption efficiency amt
recovered/amt added is plotted versus amount of analyte found. This
curve is used to correct for adsorption losses.
6. Calibration and standards.
A series of standards, varying in concentration over the range of
interest, is prepared and analyzed under the same GC conditions and
during the same time period as the unknown samples. Curves are prepared
by plotting concentration versus peak area.
Note: Since no internal standard is used in the method, standard
solutions must be analyzed at the same time that the sample analysis is
done. This will minimize the effect of known day-to-day variations and
variations during the same day of the NPD response. Multiple injections
are necessary.
7. Calculations.
Read the weight, corresponding to each peak area from the standard
curve, correct for the blank, correct for the desorption efficiency, and
make necessary air volume corrections.
8. Reference. NIOSH Method S-156.
[43 FR 45809, Oct. 3, 1978, as amended at 45 FR 35283, May 23, 1980; 54
FR 24334, June 7, 1989; 58 FR 35310, June 30, 1993; 61 FR 5508, Feb. 13,
1996; 63 FR 1291, Jan. 8, 1998; 63 FR 20099, Apr. 23, 1998]