[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: 29CFR1910.1050]
[Page 380-397]
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. 1910.1050 Methylenedianiline.
(a) Scope and application. (1) This section applies to all
occupational exposures to MDA, Chemical Abstracts Service Registry No.
101-77-9, except as provided in paragraphs (a)(2) through (a)(7) of this
section.
(2) Except as provided in paragraphs (a)(8) and (e)(5) of this
section, this section does not apply to the processing, use, and
handling of products containing MDA where initial monitoring indicates
that the product is not capable of releasing MDA in excess of the action
level under the expected conditions of processing, use, and handling
which will cause the greatest possible release; and where no ``dermal
exposure to MDA'' can occur.
(3) Except as provided in paragraph (a)(8) of this section, this
section does not apply to the processing, use, and handling of products
containing MDA where objective data are reasonably relied upon which
demonstrate the product is not capable of releasing MDA under the
expected conditions of processing, use, and handling which will cause
the greatest possible release; and where no ``dermal exposure to MDA''
can occur.
(4) This section does not apply to the storage, transportation,
distribution or sale of MDA in intact containers sealed in such a manner
as to contain the MDA dusts, vapors, or liquids, except for the
provisions of 29 CFR 1910.1200 and paragraph (d) of this section.
(5) This section does not apply to the construction industry as
defined in 29 CFR 1910.12(b). (Exposure to MDA in the construction
industry is covered by 29 CFR 1926.60).
(6) Except as provided in paragraph (a)(8) of this secton, this
section does not apply to materials in any form which contain less than
0.1% MDA by weight or volume.
(7) Except as provided in paragraph (a)(8) of this section, this
section does not apply to ``finished articles containing MDA.''
(8) Where products containing MDA are exempted under paragraphs
(a)(2) through (a)(7) of this section, the employer shall maintain
records of the initial monitoring results or objective data supporting
that exemption and the basis for the employer's reliance on the data, as
provided in the recordkeeping provision of paragraph (n) of this
section.
(b) Definitions. For the purpose of this section, the following
definitions shall apply:
Action level means a concentration of airborne MDA of 5 ppb 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 right to observe monitoring
and measuring procedures under paragraph (o) of this section, or any
other person authorized by the Act or regulations issued under the Act.
Container means any barrel, bottle, can, cylinder, drum, reaction
vessel, storage tank, commercial packaging or the like, but does not
include piping systems.
Dermal exposure to MDA occurs where employees are engaged in the
handling, application or use of mixtures or materials containing MDA,
with any of the following non-airborne forms of MDA:
(i) Liquid, powdered, granular, or flaked mixtures containing MDA in
concentrations greater than 0.1% by weight or volume; and
(ii) Materials other than ``finished articles'' containing MDA in
concentrations greater than 0.1% by weight or volume.
[[Page 381]]
Director means the Director of the 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 and potentially hazardous
release of MDA.
Employee exposure means exposure to MDA which would occur if the
employee were not using respirators or protective work clothing and
equipment.
Finished article containing MDA is defined as a manufactured item:
(i) Which is formed to a specific shape or design during
manufacture;
(ii) Which has end use function(s) dependent in whole or part upon
its shape or design during end use; and
(iii) Where applicable, is an item which is fully cured by virtue of
having been subjected to the conditions (temperature, time) necessary to
complete the desired chemical reaction.
4,4' Methylenedianiline or MDA means the chemical, 4,4'-
diaminodiphenylmethane, Chemical Abstract Service Registry number 101-
77-9, in the form of a vapor, liquid, or solid. The definition also
includes the salts of MDA.
Regulated areas means areas where airborne concentrations of MDA
exceed or can reasonably be expected to exceed, the permissible exposure
limits, or where dermal exposure to MDA can occur.
STEL means short term exposure limit as determined by any 15 minute
sample period.
(c) Permissible exposure limits (PEL). The employer shall assure
that no employee is exposed to an airborne concentration of MDA in
excess of ten parts per billion (10 ppb) as an 8-hour time-weighted
average or a STEL of 100 ppb.
(d) Emergency situations--(1) Written plan. (i) A written plan for
emergency situations shall be developed for each workplace where there
is a possibility of an emergency. 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 with the appropriate
personal protective equipment and clothing as required in paragraphs (h)
and (i) of this section until the emergency is abated.
(iii) The plan shall specifically include provisions for alerting
and evacuating affected employees as well as the elements prescribed in
29 CFR 1910.38 and 29 CFR 1910.39, ``Emergency action plans'' and ``Fire
prevention plans,'' respectively.
(2) Alerting employees. Where there is the possibility of employee
exposure to MDA due to an emergency, means shall be developed to alert
promptly those employees who have the potential to be directly exposed.
Affected employees not engaged in correcting emergency conditions shall
be evacuated immediately in the event that an emergency occurs. Means
shall also be developed and implemented for alerting other employees who
may be exposed as a result of the emergency.
(e) Exposure monitoring--(1) General. (i) Determinations of employee
exposure shall be made from breathing zone air samples that are
representative of each employee's exposure to airborne MDA over an eight
(8) hour period. Determination of employee exposure to the STEL shall be
made from breathing zone air samples collected over a 15 minute sampling
period.
(ii) Representative employee exposure shall be determined on the
basis of one or more samples representing full shift exposure for each
shift for each job classification in each work area where exposure to
MDA may occur.
(iii) Where the employer can document that exposure levels are
equivalent for similar operations in different work shifts, the employer
shall only be required to determine representative employee exposure for
that operation during one shift.
(2) Initial monitoring. Each employer who has a workplace or work
operation covered by this standard shall perform initial monitoring to
determine accurately the airborne concentrations of MDA to which
employees may be exposed.
[[Page 382]]
(3) Periodic monitoring and monitoring frequency. (i) If the
monitoring required by paragraph (e)(2) of this section reveals employee
exposure at or above the action level, but at or below the PELs, the
employer shall repeat such representative monitoring for each such
employee at least every six (6) months.
(ii) If the monitoring required by paragraph (e)(2) of this section
reveals employee exposure above the PELs, the employer shall repeat such
monitoring for each such employee at least every three (3) months.
(iii) The employer may alter the monitoring schedule from every
three months to every six months for any employee for whom two
consecutive measurements taken at least 7 days apart indicate that the
employee exposure has decreased to below the TWA but above the action
level.
(4) Termination of monitoring. (i) If the initial monitoring
required by paragraph (e)(2) of this section reveals employee exposure
to be below the action level, the employer may discontinue the
monitoring for that employee, except as otherwise required by paragraph
(e)(5) of this section.
(ii) If the periodic monitoring required by paragraph (e)(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 the employer may discontinue the monitoring for that
employee, except as otherwise required by paragraph (e)(5) of this
section.
(5) Additional monitoring. The employer shall institute the exposure
monitoring required under paragraphs (e)(2) and (e)(3) of this section
when there has been a change in production process, chemicals present,
control equipment, personnel, or work practices which may result in new
or additional exposures to MDA, or when the employer has any reason to
suspect a change which may result in new or additional exposures.
(6) Accuracy of monitoring. Monitoring shall be accurate, to a
confidence level of 95 percent, to within plus or minus 25 percent for
airborne concentrations of MDA.
(7) Employee notification of monitoring results. (i) The employer
shall, within 15 working days after the receipt of the results of any
monitoring performed under this standard, notify each employee of these
results, in writing, either individually or by posting of results in an
appropriate location that is accessible to affected employees.
(ii) The written notification required by paragraph (e)(7)(i) of
this section shall contain the corrective action being taken by the
employer to reduce the employee exposure to or below the PELs, wherever
the PELs are exceeded.
(8) Visual monitoring. The employer shall make routine inspections
of employee hands, face and forearms potentially exposed to MDA. Other
potential dermal exposures reported by the employee must be referred to
the appropriate medical personnel for observation. If the employer
determines that the employee has been exposed to MDA the employer shall:
(i) Determine the source of exposure;
(ii) Implement protective measures to correct the hazard; and
(iii) Maintain records of the corrective actions in accordance with
paragraph (n) of this section.
(f) Regulated areas--(1) Establishment--(i) Airborne exposures. The
employer shall establish regulated areas where airborne concentrations
of MDA exceed or can reasonably be expected to exceed, the permissible
exposure limits.
(ii) Dermal exposures. Where employees are subject to dermal
exposure to MDA the employer shall establish those work areas as
regulated areas.
(2) Demarcation. Regulated areas shall be demarcated from the rest
of the workplace in a manner that minimizes the number of persons
potentially exposed.
(3) Access. Access to regulated areas shall be limited to authorized
persons.
(4) Personal protective equipment and clothing. Each person entering
a regulated area shall be supplied with, and required to use, the
appropriate personal protective clothing and equipment in accordance
with paragraphs (h) and (i) of this section.
(5) Prohibited activities. The employer shall ensure that employees
do not eat, drink, smoke, chew tobacco or gum, or apply cosmetics in
regulated areas.
[[Page 383]]
(g) 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 MDA at or
below the PELs except to the extent that the employer can establish that
these controls are not feasible or where the provisions of paragraph
(g)(1)(ii) or (h)(1) (i) through (iv) of this section apply.
(ii) Wherever the feasible engineering controls and work practices
which can be instituted are not sufficient to reduce employee exposure
to or below the PELs, 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 protective devices which
comply 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 exposure to or below the
PELs by means of engineering and work practice controls, as required by
paragraph (g)(1) of this section, and by use of respiratory protection
where permitted under this section. The program shall include a schedule
for periodic maintenance (e.g., leak detection) and shall include the
written plan for emergency situations as specified in paragraph (d) of
this section.
(ii) Upon request this written program shall be furnished for
examination and copying to the Assistant Secretary, the Director,
affected employees, and designated employee representatives. The
employer shall review and, as necessary, update such plans at least once
every 12 months to make certain they reflect the current status of the
program.
(3) Employee rotation. Employee rotation shall not be permitted as a
means of reducing exposure.
(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 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 PEL.
(iv) Emergencies.
(2) Respirator program. The employer must implement a respiratory
protection program in accordance with 29 CFR 1910.134 (b) through (d)
(except (d)(1)(iii)), and (f) through (m).
(3) Respirator selection. (i) The employer must select, and ensure
that employees use, the appropriate respirator from Table 1 in this
section.
Table 1--Respiratory Protection for MDA
------------------------------------------------------------------------
Airborne concentration of MDA
or condition of use Respirator type
------------------------------------------------------------------------
a. Less than or equal to 10 x (1) Half-Mask Respirator with HEPA \1\
PEL. Cartridge.\2\
b. Less than or equal to 50 x (1) Full facepiece Respirator with HEPA
PEL. \1\ Cartridge or Canister.\2\
c. Less than or equal to 1000 (1) Full facepiece powered air-purifying
x PEL. respirator with HEPA \1\ cartridges.\2\
d. Greater than 1000 x PEL or (1) Self-contained breathing apparatus
unknown concentrations. with full facepiece in positive pressure
mode.
(2) Full facepiece positive pressure
demand supplied-air respirator with
auxiliary self-contained air supply.
e. Escape.................... (1) Any full facepiece air-purifying
respirator with HEPA \1\ cartridges; \2\
(2) Any positive pressure or continuous
flow self-contained breathing apparatus
with full facepiece or hood.
f. Firefighting.............. (1) Full facepiece self-contained
breathing apparatus in positive pressure
demand mode.
------------------------------------------------------------------------
Note: Respirators assigned for higher environmental concentrations may
be used at lower concentrations.
\1\ High Efficiency Particulate in Air filter (HEPA) means a filter that
is at least 99.97 percent efficient against mono-dispersed particles
of 0.3 micrometers or larger.
\2\ Combination HEPA/Organic Vapor Cartridges shall be used whenever MDA
in liquid form or a process requiring heat is used.
[[Page 384]]
(ii) Any employee who cannot use a negative-pressure respirator must
be given the option of using a positive-pressure respirator, or a
supplied-air respirator operated in the continuous-flow or pressure-
demand mode.
(i) Protective work clothing and equipment--(1) Provision and use.
Where employees are subject to dermal exposure to MDA, where liquids
containing MDA can be splashed into the eyes, or where airborne
concentrations of MDA are in excess of the PEL, the employer shall
provide, at no cost to the employee, and ensure that the employee uses,
appropriate protective work clothing and equipment which prevent contact
with MDA such as, but not limited to:
(i) Aprons, coveralls or other full-body work clothing;
(ii) Gloves, head coverings, and foot coverings; and
(iii) Face shields, chemical goggles; or
(iv) Other appropriate protective equipment which comply with
Sec. 1910.133.
(2) Removal and storage. (i) The employer shall ensure that, at the
end of their work shift, employees remove MDA-contaminated protective
work clothing and equipment that is not routinely removed throughout the
day in change rooms provided in accordance with the provisions
established for change rooms.
(ii) The employer shall ensure that, during their work shift,
employees remove all other MDA-contaminated protective work clothing or
equipment before leaving a regulated area.
(iii) The employer shall ensure that no employee takes MDA-
contaminated work clothing or equipment out of the change room, except
those employees authorized to do so for the purpose of laundering,
maintenance, or disposal.
(iv) MDA-contaminated work clothing or equipment shall be placed and
stored in closed containers which prevent dispersion of the MDA outside
the container.
(v) Containers of MDA-contaminated protective work clothing or
equipment which are to be taken out of change rooms or the workplace for
cleaning, maintenance, or disposal, shall bear labels warning of the
hazards of MDA.
(3) Cleaning and replacement. (i) The employer shall provide the
employee with clean protective clothing and equipment. The employer
shall ensure that protective work clothing or equipment required by this
paragraph is cleaned, laundered, repaired, or replaced at intervals
appropriate to maintain its effectiveness.
(ii) The employer shall prohibit the removal of MDA from protective
work clothing or equipment by blowing, shaking, or any methods which
allow MDA to re-enter the workplace.
(iii) The employer shall ensure that laundering of MDA-contaminated
clothing shall be done so as to prevent the release of MDA in the
workplace.
(iv) Any employer who gives MDA-contaminated clothing to another
person for laundering shall inform such person of the requirement to
prevent the release of MDA.
(v) The employer shall inform any person who launders or cleans
protective clothing or equipment contaminated with MDA of the
potentially harmful effects of exposure.
(vi) MDA-contaminated clothing shall be transported in properly
labeled, sealed, impermeable bags or containers.
(j) Hygiene facilities and practices--(1) Change rooms. (i) The
employer shall provide clean change rooms for employees, who must wear
protective clothing, or who must use protective equipment because of
their exposure to MDA.
(ii) Change rooms must be equipped with separate storage for
protective clothing and equipment and for street clothes which prevents
MDA contamination of street clothes.
(2) Showers. (i) The employer shall ensure that employees, who work
in areas where there is the potential for exposure resulting from
airborne MDA (e.g., particulates or vapors) above the action level,
shower at the end of the work shift.
(A) Shower facilities required by this paragraph shall comply with
Sec. 1910.141(d)(3).
(B) The employer shall ensure that employees who are required to
shower pursuant to the provisions contained herein do not leave the
workplace
[[Page 385]]
wearing any protective clothing or equipment worn during the work shift.
(ii) Where dermal exposure to MDA occurs, the employer shall ensure
that materials spilled or deposited on the skin are removed as soon as
possible by methods which do not facilitate the dermal absorption of
MDA.
(3) Lunch facilities--(i) Availability and construction. (A)
Whenever food or beverages are consumed at the worksite and employees
are exposed to MDA at or above the PEL or are subject to dermal exposure
to MDA the employer shall provide readily accessible lunch areas.
(B) Lunch areas located within the workplace and in areas where
there is the potential for airborne exposure to MDA at or above the PEL
shall have a positive pressure, temperature controlled, filtered air
supply.
(C) Lunch areas may not be located in areas within the workplace
where the potential for dermal exposure to MDA exists.
(ii) The employer shall ensure that employees who have been
subjected to dermal exposure to MDA or who have been exposed to MDA
above the PEL wash their hands and faces with soap and water prior to
eating, drinking, smoking, or applying cosmetics.
(iii) The employer shall ensure that employees exposed to MDA do not
enter lunch facilities with MDA-contaminated protective work clothing or
equipment.
(k) Communication of hazards to employees--(1) Signs and labels. (i)
The employer shall post and maintain legible signs demarcating regulated
areas and entrances or accessways to regulated areas that bear the
following legend:
DANGER
MDA MAY CAUSE CANCER LIVER TOXIN
AUTHORIZED PERSONNEL ONLY
RESPIRATORS AND PROTECTIVE CLOTHING
MAY BE REQUIRED TO BE WORN IN THIS AREA
(ii) The employer shall ensure that labels or other appropriate
forms of warning are provided for containers of MDA within the
workplace. The labels shall comply with the requirements of 29 CFR
1910.1200(f) and shall include the following legend:
(A) For Pure MDA
DANGER
CONTAINS MDA
MAY CAUSE CANCER LIVER TOXIN
(B) For mixtures containing MDA
DANGER
CONTAINS MDA
CONTAINS MATERIALS WHICH MAY CAUSE
CANCER LIVER TOXIN
(2) Material safety data sheets (MSDS). (i) Employers shall obtain
or develop, and shall provide access to their employees, to a material
safety data sheet (MSDS) for MDA. In meeting this obligation, employers
shall make appropriate use of the information found in Appendices A and
B.
(ii) Employers who are manufacturers or importers shall:
(A) Comply with paragraph (k) (1) (ii) of this section as
appropriate, and
(B) Comply with the requirement in OSHA's Hazard Communication
standard, 29 CFR 1910.1200, that they deliver to downstream employers an
MSDS for MDA.
(3) Information and training. (i) The employer shall provide
employees with information and training on MDA, in accordance with 29
CFR 1910.1200(h), at the time of initial assignment and at least
annually thereafter.
(ii) In addition to the information required under 29 CFR 1910.1200,
the employer shall:
(A) Provide an explanation of the contents of this section,
including appendices A and B, and indicate to employees where a copy of
the standard is available;
(B) Describe the medical surveillance program required under
paragraph (m) of this section, and explain the information contained in
Appendix C; and
(C) Describe the medical removal provision required under paragraph
(m) of this section.
(4) Access to training materials. (i) The employer shall make
readily available to all affected employees, without cost, all written
materials relating to the employee training program, including a copy of
this regulation.
(ii) The employer shall provide to the Assistant Secretary and the
Director, upon request, all information and
[[Page 386]]
training materials relating to the employee information and training
program.
(l) Housekeeping. (1) All surfaces shall be maintained as free as
practicable of visible accumulations of MDA.
(2) The employer shall institute a program for detecting MDA leaks,
spills, and discharges, including regular visual inspections of
operations involving liquid or solid MDA.
(3) All leaks shall be repaired and liquid or dust spills cleaned up
promptly.
(4) Surfaces contaminated with MDA may not be cleaned by the use of
compressed air.
(5) Shoveling, dry sweeping, and other methods of dry clean-up of
MDA may be used where HEPA-filtered vacuuming and/or wet cleaning are
not feasible or practical.
(6) Waste, scrap, debris, bags, containers, equipment, and clothing
contaminated with MDA shall be collected and disposed of in a manner to
prevent the re-entry of MDA into the workplace.
(m) Medical surveillance--(1) General. (i) The employer shall make
available a medical surveillance program for employees exposed to MDA:
(A) Employees exposed at or above the action level for 30 or more
days per year;
(B) Employees who are subject to dermal exposure to MDA for 15 or
more days per year;
(C) Employees who have been exposed in an emergency situation;
(D) Employees whom the employer, based on results from compliance
with paragraph (e)(8) of this section, has reason to believe are being
dermally exposed; and
(E) Employees who show signs or symptoms of MDA exposure.
(ii) The employer shall ensure that all medical examinations and
procedures are performed by, or under the supervision of, a licensed
physician, at a reasonable time and place, and provided without cost to
the employee.
(2) Initial examinations. (i) Within 150 days of the effective date
of this standard, or before the time of initial assignment, the employer
shall provide each employee covered by paragraph (m)(1)(i) of this
section with a medical examination including the following elements:
(A) A detailed history which includes:
(1) Past work exposure to MDA or any other toxic substances;
(2) A history of drugs, alcohol, tobacco, and medication routinely
taken (duration and quantity); and
(3) A history of dermatitis, chemical skin sensitization, or
previous hepatic disease.
(B) A physical examination which includes all routine physical
examination parameters, skin examination, and signs of liver disease.
(C) Laboratory tests including:
(1) Liver function tests and
(2) Urinalysis.
(D) Additional tests as necessary in the opinion of the physician.
(ii) No initial medical examination is required if adequate records
show that the employee has been examined in accordance with the
requirements of this section within the previous six months prior to the
effective date of this standard or prior to the date of initial
assignment.
(3) Periodic examinations. (i) The employer shall provide each
employee covered by this section with a medical examination at least
annually following the initial examination. These periodic examinations
shall include at least the following elements:
(A) A brief history regarding any new exposure to potential liver
toxins, changes in drug, tobacco, and alcohol intake, and the appearance
of physical signs relating to the liver, and the skin;
(B) The appropriate tests and examinations including liver function
tests and skin examinations; and
(C) Appropriate additional tests or examinations as deemed necessary
by the physician.
(ii) If in the physicians' opinion the results of liver function
tests indicate an abnormality, the employee shall be removed from
further MDA exposure in accordance with paragraph (m)(9) of this
section. Repeat liver function tests shall be conducted on advice of the
physician.
(4) Emergency examinations. If the employer determines that the
employee
[[Page 387]]
has been exposed to a potentially hazardous amount of MDA in an
emergency situation as addressed in paragraph (d) of this section, the
employer shall provide medical examinations in accordance with
paragraphs (m)(3)(i) and (ii) of this section. If the results of liver
function testing indicate an abnormality, the employee shall be removed
in accordance with paragraph (m)(9) of this section. Repeat liver
function tests shall be conducted on the advice of the physician. If the
results of the tests are normal, tests must be repeated two to three
weeks from the initial testing. If the results of the second set of
tests are normal and, on the advice of the physician, no additional
testing is required.
(5) Additional examinations. Where the employee develops signs and
symptoms associated with exposure to MDA, the employer shall provide the
employee with an additional medical examination including a liver
function test. Repeat liver function tests shall be conducted on the
advice of the physician. If the results of the tests are normal, tests
must be repeated two to three weeks from the initial testing. If the
results of the second set of tests are normal and, on the advice of the
physician, no additional testing is required.
(6) Multiple physician review mechanism. (i) If the employer selects
the initial physician who conducts any medical examination or
consultation provided to an employee under this section, and the
employee has signs or symptoms of occupational exposure to MDA (which
could include an abnormal liver function test), and the employee
disagrees with the opinion of the examining physician, and this opinion
could affect the employee's job status, the employee may designate an
appropriate, mutually acceptable second physician:
(A) To review any findings, determinations, or recommendations of
the initial physician; and
(B) To conduct such examinations, consultations, and laboratory
tests as the second physician deems necessary to facilitate this review.
(ii) The employer shall promptly notify an employee of the right to
seek a second medical opinion after each occasion that an initial
physician conducts a medical examination or consultation pursuant to
this section. The employer may condition its participation in, and
payment for, the multiple physician review mechanism upon the employee
doing the following within fifteen (15) days after receipt of the
foregoing notification, or receipt of the initial physician's written
opinion, whichever is later:
(A) The employee informing the employer that he or she intends to
seek a second medical opinion, and
(B) The employee initiating steps to make an appointment with a
second physician.
(iii) If the findings, determinations, or recommendations of the
second physician differ from those of the initial physician, then the
employer and the employee shall assure that efforts are made for the two
physicians to resolve any disagreement.
(iv) If the two physicians have been unable to resolve quickly their
disagreement, then the employer and the employee through their
respective physicians shall designate a third physician;
(A) To review any findings, determinations, or recommendations of
the prior physicians; and
(B) To conduct such examinations, consultations, laboratory tests,
and discussions with the prior physicians as the third physician deems
necessary to resolve the disagreement of the prior physicians.
(v) The employer shall act consistent with the findings,
determinations, and recommendations of the third physician, unless the
employer and the employee reach an agreement which is otherwise
consistent with the recommendations of at least one of the three
physicians.
(7) Information provided to the examining and consulting physicians.
(i) The employer shall provide the following information to the
examining physician:
(A) A copy of this regulation and its appendices;
(B) A description of the affected employee's duties as they relate
to the employee's potential exposure to MDA;
(C) The employee's current actual or representative MDA exposure
level;
[[Page 388]]
(D) A description of any personal protective equipment used or to be
used; and
(E) Information from previous employment-related medical
examinations of the affected employee.
(ii) The employer shall provide the foregoing information to a
second physician under this section upon request either by the second
physician, or by the employee.
(8) Physician's written opinion. (i) For each examination under this
section, the employer shall obtain, and provide the employee with a copy
of, the examining physician's written opinion within 15 days of its
receipt. The written opinion shall include the following:
(A) The occupationally-pertinent results of the medical examination
and tests;
(B) The physician's opinion concerning whether the employee has any
detected medical conditions which would place the employee at increased
risk of material impairment of health from exposure to MDA;
(C) The physician's recommended limitations upon the employee's
exposure to MDA or upon the employee's use of protective clothing or
equipment and 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
resulting from MDA exposure which require further explanation or
treatment.
(ii) The written opinion obtained by the employer shall not reveal
specific findings or diagnoses unrelated to occupational exposures.
(9) Medical removal--(i) Temporary medical removal of an employee--
(A) Temporary removal resulting from occupational exposure. The employee
shall be removed from work environments in which exposure to MDA is at
or above the action level or where dermal exposure to MDA may occur,
following an initial examination (paragraph (m)(2) of this section),
periodic examinations (paragraph (m)(3) of this section), an emergency
situation paragraph (m)(4) of this section, or an additional examination
(paragraph (m)(5) of this section) in the following circumstances:
(1) When the employee exhibits signs and/or symptoms indicative of
acute exposure to MDA; or
(2) When the examining physician determines that an employee's
abnormal liver function tests are not associated with MDA exposure but
that the abnormalities may be exacerbated as a result of occupational
exposure to MDA.
(B) Temporary removal due to a final medical determination. (1) The
employer shall remove an employee from work environments in which
exposure to MDA is at or above the action level or where dermal exposure
to MDA may occur, on each occasion that there is a final medical
determination or opinion that the employee has a detected medical
condition which places the employee at increased risk of material
impairment to health from exposure to MDA.
(2) For the purposes of this section, the phrase ``final medical
determination'' shall mean the outcome of the physician review mechanism
used pursuant to the medical surveillance provisions of this section.
(3) Where a final medical determination results in any recommended
special protective measures for an employee, or limitations on an
employee's exposure to MDA, the employer shall implement and act
consistent with the recommendation.
(ii) Return of the employee to former job status. (A) The employer
shall return an employee to his or her former job status:
(1) When the employee no longer shows signs or symptoms of exposure
to MDA, or upon the advice of the physician.
(2) When a subsequent final medical determination results in a
medical finding, determination, or opinion that the employee no longer
has a detected medical condition which places the employee at increased
risk of material impairment to health from exposure to MDA.
(B) For the purposes of this section, the requirement that an
employer return an employee to his or her former job status is not
intended to expand upon or restrict any rights an employee has or would
have had, absent temporary medical removal, to a specific job
classification or position
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under the terms of a collective bargaining agreement.
(iii) Removal of other employee special protective measure or
limitations. The employer shall remove any limitations placed on an
employee, or end any special protective measures provided to an
employee, pursuant to a final medical determination, when a subsequent
final medical determination indicates that the limitations or special
protective measures are no longer necessary.
(iv) Employer options pending a final medical determination. Where
the physician review mechanism used pursuant to the medical surveillance
provisions of this section, has not yet resulted in a final medical
determination with respect to an employee, the employer shall act as
follows:
(A) Removal. The employer may remove the employee from exposure to
MDA, provide special protective measures to the employee, or place
limitations upon the employee, consistent with the medical findings,
determinations, or recommendations of any of the physicians who have
reviewed the employee's health status.
(B) Return. The employer may return the employee to his or her
former job status, and end any special protective measures provided to
the employee, consistent with the medical findings, determinations, or
recommendations of any of the physicians who have reviewed the
employee's health status, with two exceptions.
(1) If the initial removal, special protection, or limitation of the
employee resulted from a final medical determination which differed from
the findings, determinations, or recommendations of the initial
physician; or
(2) If the employee has been on removal status for the preceding six
months as a result of exposure to MDA, then the employer shall await a
final medical determination.
(v) Medical removal protection benefits--(A) Provisions of medical
removal protection benefits. The employer shall provide to an employee
up to six (6) months of medical removal protection benefits on each
occasion that an employee is removed from exposure to MDA or otherwise
limited pursuant to this section.
(B) Definition of medical removal protection benefits. For the
purposes of this section, the requirement that an employer provide
medical removal protection benefits means that the employer shall
maintain the earnings, seniority, and other employment rights and
benefits of an employee as though the employee had not been removed from
normal exposure to MDA or otherwise limited.
(C) Follow-up medical surveillance during the period of employee
removal or limitations. During the period of time that an employee is
removed from normal exposure to MDA or otherwise limited, the employer
may condition the provision of medical removal protection benefits upon
the employee's participation in follow-up medical surveillance made
available pursuant to this section.
(D) Workers' compensation claims. If a removed employee files a
claim for workers' compensation payments for a MDA-related disability,
then the employer shall continue to provide medical removal protection
benefits pending disposition of the claim. To the extent that an award
is made to the employee for earnings lost during the period of removal,
the employer's medical removal protection obligation shall be reduced by
such amount. The employer shall receive no credit for workers'
compensation payments received by the employee for treatment-related
expenses.
(E) Other credits. The employer's obligation to provide medical
removal protection benefits to a removed employee shall be reduced to
the extent that the employee receives compensation for earnings lost
during the period of removal either from a publicly or employer-funded
compensation program, or receives income from non-MDA-related employment
with any employer made possible by virtue of the employee's removal.
(F) Employees who do not recover within the 6 months of removal. The
employer shall take the following measures with respect to any employee
removed from exposure to MDA:
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(1) The employer shall make available to the employee a medical
examination pursuant to this section to obtain a final medical
determination with respect to the employee;
(2) The employer shall assure that the final medical determination
obtained indicates whether or not the employee may be returned to his or
her former job status, and, if not, what steps should be taken to
protect the employee's health;
(3) Where the final medical determination has not yet been obtained,
or, once obtained indicates that the employee may not yet be returned to
his or her former job status, the employer shall continue to provide
medical removal protection benefits to the employee until either the
employee is returned to former job status, or a final medical
determination is made that the employee is incapable of ever safely
returning to his or her former job status; and
(4) Where the employer acts pursuant to a final medical
determination which permits the return of the employee to his or her
former job status, despite what would otherwise be an abnormal liver
function test, later questions concerning removing the employee again
shall be decided by a final medical determination. The employer need not
automatically remove such an employee pursuant to the MDA removal
criteria provided by this section.
(vi) Voluntary removal or restriction of an employee. Where an
employer, although not required by this section to do so, removes an
employee from exposure to MDA or otherwise places limitations on an
employee due to the effects of MDA exposure on the employee's medical
condition, the employer shall provide medical removal protection
benefits to the employee equal to that required by paragraph (m)(9)(v)
of this section.
(n) Recordkeeping--(1) Monitoring data for exempted employers. (i)
Where as a result of the initial monitoring the processing, use, or
handling of products made from or containing MDA are exempted from other
requirements of this section under paragraph (a)(2) of this section, the
employer shall establish and maintain an accurate record of monitoring
relied on in support of the exemption.
(ii) This record shall include at least the following information:
(A) The product qualifying for exemption;
(B) The source of the monitoring data (e.g., was monitoring
performed by the employer or a private contractor);
(C) The testing protocol, results of testing, and/or analysis of the
material for the release of MDA;
(D) A description of the operation exempted and how the data support
the exemption (e.g., are the monitoring data representative of the
conditions at the affected facility); 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) Objective data for exempted employers. (i) Where the processing,
use, or handling of products made from or containing MDA are exempted
from other requirements of this section under paragraph (a) of this
section, the employer shall establish and maintain an accurate record of
objective data relied upon in support of the exemption.
(ii) This record shall include at least the following information:
(A) The product 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 MDA;
(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.
(3) Exposure measurements. (i) The employer shall establish and
maintain an accurate record of all measurements required by paragraph
(e) of this section, in accordance with 29 CFR 1910.20.
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(ii) This record shall include:
(A) The dates, number, duration, and results of each of the samples
taken, including a description of the procedure used to determine
representative employee exposures;
(B) Identification of the sampling and analytical methods used;
(C) A description of the type of respiratory protective devices
worn, if any; and
(D) The name, social security number, job classification and
exposure levels of the employee monitored and all other employees whose
exposure the measurement is intended to represent.
(iii) The employer shall maintain this record for at least 30 years,
in accordance with 29 CFR 1910.20.
(4) Medical surveillance. (i) The employer shall establish and
maintain an accurate record for each employee subject to medical
surveillance required by paragraph (m) of this section, in accordance
with 29 CFR 1910.20.
(ii) This record shall include:
(A) The name, social security number and description of the duties
of the employee;
(B) The employer's copy of the physician's written opinion on the
initial, periodic, and any special examinations, including results of
medical examination and all tests, opinions, and recommendations;
(C) Results of any airborne exposure monitoring done for that
employee and the representative exposure levels supplied to the
physician; and
(D) Any employee medical complaints related to exposure to MDA;
(iii) The employer shall keep, or assure that the examining
physician keeps, the following medical records:
(A) A copy of this standard and its appendices, except that the
employer may keep one copy of the standard and its appendices for all
employees provided the employer references the standard and its
appendices in the medical surveillance record of each employee;
(B) A copy of the information provided to the physician as required
by any paragraphs in the regulatory text;
(C) A description of the laboratory procedures and a copy of any
standards or guidelines used to interpret the test results or references
to the information;
(D) A copy of the employee's medical and work history related to
exposure to MDA; and
(iv) The employer shall maintain this record for at least the
duration of employment plus 30 years, in accordance with 29 CFR 1910.20.
(5) Medical removals. (i) The employer shall establish and maintain
an accurate record for each employee removed from current exposure to
MDA pursuant to paragraph (m) of this section.
(ii) Each record shall include:
(A) The name and social security number of the employee;
(B) The date of each occasion that the employee was removed from
current exposure to MDA as well as the corresponding date on which the
employee was returned to his or her former job status;
(C) A brief explanation of how each removal was or is being
accomplished; and
(D) A statement with respect to each removal indicating the reason
for the removal.
(iii) The employer shall maintain each medical removal record for at
least the duration of an employee's employment plus 30 years.
(6) Availability. (i) The employer shall assure that records
required to be maintained by this section shall be made available, upon
request, to the Assistant Secretary and the Director for examination and
copying.
(ii) Employee exposure monitoring records required by this section
shall be provided upon request for examination and copying to employees,
employee representatives, and the Assistant Secretary in accordance with
29 CFR 1910.20 (a)-(e) and (g)-(i).
(iii) Employee medical records required by this section shall be
provided upon request for examination and copying, to the subject
employee, to anyone having the specific written consent of the subject
employee, and to the Assistant Secretary in accordance with 29 CFR
1910.20.
(7) Transfer of records. (i) The employer shall comply with the
requirements involving transfer of records set forth in 29 CFR
1910.20(h).
[[Page 392]]
(ii) If the employer ceases to do business and there is no successor
employer to receive and retain the records for the prescribed period,
the employer shall notify the Director, at least 90 days prior to
disposal, and transmit the records to the Director if so requested by
the Director within that period.
(o) Observation of monitoring--(1) Employee observation. The
employer shall provide affected employees, or their designated
representatives, an opportunity to observe the measuring or monitoring
of employee exposure to MDA conducted pursuant to paragraph (e) of this
section.
(2) Observation procedures. When observation of the measuring or
monitoring of employee exposure to MDA requires entry into areas where
the use of protective clothing and equipment or respirators is required,
the employer shall provide the observer with personal protective
clothing and equipment or respirators required to be worn by employees
working in the area, assure the use of such clothing and equipment or
respirators, and require the observer to comply with all other
applicable safety and health procedures.
(p) Effective date. This standard shall become effective September
9, 1992.
(q) Appendices. The information contained in appendices A, B, C and
D of this section is not intended by itself, to create any additional
obligations not otherwise imposed by this standard nor detract from any
existing obligation. The protocols for respiratory fit testing in
appendix E of this section are mandatory.
(r) Startup dates. Compliance with all obligations of this standard
commence on the effective date except as follows:
(1) Initial monitoring under paragraph (e)(2) of this section shall
be completed as soon as possible but no later than December 8, 1992.
(2) Medical examinations under paragraph (m) of this section shall
be completed as soon as possible but no later than February 8, 1993.
(3) Emergency plans required by paragraph (d) of this section shall
be provided and available for inspection and copying as soon as possible
but no later than January 7, 1993.
(4) Initial training and education shall be completed as soon as
possible but no later than January 7, 1993.
(5) Hygiene and lunchroom facilities under paragraph (j) shall be in
operation as soon as possible but no later than September 9, 1993.
(6) Respiratory Protection required by paragraph (h) of this section
shall be provided as soon as possible but no later than January 7, 1993.
(7) Written compliance plans required by paragraph (g)(2) of this
section shall be completed and available for inspection and copying as
soon as possible but no later than January 7, 1993.
(8) OSHA shall enforce the permissible exposure limits in paragraph
(c) of this section no earlier than January 7, 1993.
(9) Engineering controls needed to achieve the PELs must be in place
September 9, 1993.
(10) Personal protective clothing required by paragraph (i) of this
section shall be available January 7, 1993.
Appendix A to Sec. 1910.1050--Substance Data Sheet, for 4,4'-
Methylenedianiline
I. Substance Identification
A. Substance: Methylenedianiline (MDA)
B. Permissible Exposure:
1. Airborne: Ten parts per billion parts of air (10 ppb), time-
weighted average (TWA) for an 8-hour workday and an action level of five
parts per billion parts of air (5 ppb).
2. Dermal: Eye contact and skin contact with MDA are not permitted.
C. Appearance and odor: White to tan solid; amine odor
II. Health Hazard Data
A. Ways in which MDA affects your health. MDA can affect your health
if you inhale it, or if it comes in contact with your skin or eyes. MDA
is also harmful if you happen to swallow it. Do not get MDA in eyes, on
skin, or on clothing.
B. Effects of overexposure. 1. Short-term (acute) overexposure:
Overexposure to MDA may produce fever, chills, loss of appetite,
vomiting, jaundice. Contact may irritate skin, eyes and mucous
membranes. Sensitization may occur.
2. Long-term (chronic) exposure. Repeated or prolonged exposure to
MDA, even at relatively low concentrations, may cause cancer. In
addition, damage to the liver, kidneys, blood, and spleen may occur with
long term exposure.
3. Reporting signs and symptoms. You should inform your employer if
you develop any
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signs or symptoms which you suspect are caused by exposure to MDA
including yellow staining of the skin.
III. Protective Clothing and Equipment
A. Respirators. Respirators are required for those operations in
which engineering controls or work-practice controls are not adequate or
feasible to reduce exposure to the permissible limit. 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 this purpose, and
cartridges and canisters must be replaced in accordance with the
requirements of 29 CFR 1910.134. If you experience difficulty breathing
while wearing a respirator, you can request a positive-pressure
respirator from your employer. You must be thoroughly trained to use the
assigned respirator, and the training must be provided by your employer.
MDA does not have a detectable odor except at levels well above the
permissible exposure limits. Do not depend on odor to warn you when a
respirator canister is exhausted. If you can smell MDA while wearing a
respirator, proceed immediately to fresh air. If you experience
difficulty breathing while wearing a respirator, tell your employer.
B. Protective Clothing. You may be required to wear coveralls,
aprons, gloves, face shields, or other appropriate protective clothing
to prevent skin contact with MDA. Where protective clothing is required,
your employer is required to provide clean garments to you, as
necessary, to assure that the clothing protects you adequately. Replace
or repair impervious clothing that has developed leaks.
MDA should never be allowed to remain on the skin. Clothing and
shoes which are not impervious to MDA should not be allowed to become
contaminated with MDA, and if they do, the clothing and shoes should be
promptly removed and decontaminated. The clothing should be laundered to
remove MDA or discarded. Once MDA penetrates shoes or other leather
articles, they should not be worn again.
C. Eye protection. You must wear splashproof safety goggles in areas
where liquid MDA may contact your eyes. Contact lenses should not be
worn in areas where eye contact with MDA can occur. In addition, you
must wear a face shield if your face could be splashed with MDA liquid.
IV. Emergency and First Aid Procedures
A. Eye and face exposure. If MDA is splashed into the eyes, wash the
eyes for at least 15 minutes. See a doctor as soon as possible.
B. Skin exposure. If MDA is spilled on your clothing or skin, remove
the contaminated clothing and wash the exposed skin with large amounts
of soap and water immediately. Wash contaminated clothing before you
wear it again.
C. Breathing. If you or any other person breathes in large amounts
of MDA, get the exposed person to fresh air at once. Apply artificial
respiration if breathing has stopped. Call for medical assistance or a
doctor as soon as possible. Never enter any vessel or confined space
where the MDA concentration might be high without proper safety
equipment and at least one other person present who will stay outside. A
life line should be used.
D. Swallowing. If MDA has been swallowed and the patient is
conscious, do not induce vomiting. Call for medical assistance or a
doctor immediately.
V. Medical Requirements
If you are exposed to MDA at a concentration at or above the action
level for more than 30 days per year, or exposed to liquid mixtures more
than 15 days per year, your employer is required to provide a medical
examination, including a medical history and laboratory tests, within 60
days of the effective date of this standard and annually thereafter.
These tests shall be provided without cost to you. In addition, if you
are accidentally exposed to MDA (either by ingestion, inhalation, or
skin/eye contact) under conditions known or suspected to constitute
toxic exposure to MDA, your employer is required to make special
examinations and tests available to you.
VI. Observation of Monitoring
Your employer is required to perform measurements that are
representative of your exposure to MDA 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 and your representative must also
be provided with, and must wear, the protective clothing and equipment.
VII. Access to Records
You or your representative are entitled to see the records of
measurements of your exposure to MDA upon written request to your
employer. Your medical examination records can be furnished to your
physician or designated representative upon request by you to your
employer.
[[Page 394]]
VIII. Precautions for Safe Use, Handling and Storage
A. Material is combustible. Avoid strong acids and their anhydrides.
Avoid strong oxidants. Consult supervisor for disposal requirements.
B. Emergency clean-up. Wear self-contained breathing apparatus and
fully clothe the body in the appropriate personal protective clothing
and equipment.
Appendix B to Sec. 1910.1050--Substance Technical Guidelines, MDA
I. Identification
A. Substance identification.
1. Synonyms: CAS No. 101-77-9. 4,4'-methylenedianiline; 4,4'-
methylenebisaniline; methylenedianiline; dianilinomethane.
2. Formula: C13 H14 N2
II. Physical Data
1. Appearance and Odor: White to tan solid; amine odor
2. Molecular Weight: 198.26
3. Boiling Point: 398-399 degrees C at 760 mm Hg
4. Melting Point: 88-93 degrees C (190-100 degrees F)
5. Vapor Pressure: 9 mmHg at 232 degrees C
6. Evaporation Rate (n-butyl acetate = 1): Negligible
7. Vapor Density (Air=1): Not Applicable
8. Volatile Fraction by Weight: Negligible
9. Specific Gravity (Water=1): Slight
10. Heat of Combustion: -8.40 kcal/g
11. Solubility in Water: Slightly soluble in cold water, very
soluble in alcohol, benzene, ether, and many organic solvents.
III. Fire, Explosion, and Reactivity Hazard Data
1. Flash Point: 190 degrees C (374 degrees F) Setaflash closed cup
2. Flash Point: 226 degrees C (439 degrees F) Cleveland open cup
3. Extinguishing Media: Water spray; Dry Chemical; Carbon dioxide.
4. Special Fire Fighting Procedures: Wear self-contained breathing
apparatus and protective clothing to prevent contact with skin and eyes.
5. Unusual Fire and Explosion Hazards: Fire or excessive heat may
cause production of hazardous decomposition products.
IV. Reactivity Data
1. Stability: Stable
2. Incompatibility: Strong oxidizers
3. Hazardous Decomposition Products: As with any other organic
material, combustion may produce carbon monoxide. Oxides of nitrogen may
also be present.
4. Hazardous Polymerization: Will not occur.
V. Spill and Leak Procedures
1. Sweep material onto paper and place in fiber carton.
2. Package appropriately for safe feed to an incinerator or dissolve
in compatible waste solvents prior to incineration.
3. Dispose of in an approved incinerator equipped with afterburner
and scrubber or contract with licensed chemical waste disposal service.
4. Discharge treatment or disposal may be subject to federal, state,
or local laws.
5. Wear appropriate personal protective equipment.
VI. Special Storage and Handling Precautions
A. High exposure to MDA can occur when transferring the substance
from one container to another. Such operations should be well ventilated
and good work practices must be established to avoid spills.
B. Pure MDA is a solid with a low vapor pressure. Grinding or
heating operations increase the potential for exposure.
C. Store away from oxidizing materials.
D. Employers shall advise employees of all areas and operations
where exposure to MDA could occur.
VII. Housekeeping and Hygiene Facilities
A. The workplace should be kept clean, orderly, and in a sanitary
condition.
The employer should institute a leak and spill detection program for
operations involving MDA in order to detect sources of fugitive MDA
emissions.
B. Adequate washing facilities with hot and cold water are to be
provided and maintained in a sanitary condition. Suitable cleansing
agents should also be provided to assure the effective removal of MDA
from the skin.
VIII. Common Operations
Common operations in which exposure to MDA is likely to occur
include the following: Manufacture of MDA; Manufacture of Methylene
diisocyanate; Curing agent for epoxy resin structures; Wire coating
operations; and filament winding.
Appendix C to Sec. 1910.1050--Medical Surveillance Guidelines for MDA
I. Route of Entry
Inhalation; skin absorption; ingestion. MDA can be inhaled, absorbed
through the skin, or ingested.
II. Toxicology
MDA is a suspect carcinogen in humans. There are several reports of
liver disease in humans and animals resulting from acute exposure to
MDA. A well documented case of
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an acute cardiomyopathy secondary to exposure to MDA is on record.
Numerous human cases of hepatitis secondary to MDA are known. Upon
direct contact MDA may also cause damage to the eyes. Dermatitis and
skin sensitization have been observed. Almost all forms of acute
environmental hepatic injury in humans involve the hepatic parenchyma
and produce hepatocellular jaundice. This agent produces intrahepatic
cholestasis. The clinical picture consists of cholestatic jaundice,
preceded or accompanied by abdominal pain, fever, and chills. Onset in
about 60% of all observed cases is abrupt with severe abdominal pain. In
about 30% of observed cases, the illness presented and evolved more
slowly and less dramatically, with only slight abdominal pain. In about
10% of the cases only jaundice was evident. The cholestatic nature of
the jaundice is evident in the prominence of itching, the histologic
predominance of bile stasis, and portal inflammatory infiltration,
accompanied by only slight parenchymal injury in most cases, and by the
moderately elevated transaminase values. Acute, high doses, however,
have been known to cause hepatocellular damage resulting in elevated
SGPT, SGOT, alkaline phosphatase and bilirubin.
Absorption through the skin is rapid. MDA is metabolized and
excreted over a 48-hour period. Direct contact may be irritating to the
skin, causing dermatitis. Also MDA which is deposited on the skin is not
thoroughly removed through washing.
MDA may cause bladder cancer in humans. Animal data supporting this
assumption is not available nor is conclusive human data. However, human
data collected on workers at a helicopter manufacturing facility where
MDA is used suggests a higher incidence of bladder cancer among exposed
workers.
III. Signs and Symptoms
Skin may become yellow from contact with MDA.
Repeated or prolonged contact with MDA may result in recurring
dermatitis (red-itchy, cracked skin) and eye irritation. Inhalation,
ingestion or absorption through the skin at high concentrations may
result in hepatitis, causing symptoms such as fever and chills, nausea
and vomiting, dark urine, anorexia, rash, right upper quadrant pain and
jaundice. Corneal burns may occur when MDA is splashed in the eyes.
IV. Treatment of Acute Toxic Effects/Emergency Situation
If MDA gets into the eyes, immediately wash eyes with large amounts
of water. If MDA is splashed on the skin, immediately wash contaminated
skin with mild soap or detergent. Employee should be removed from
exposure and given proper medical treatment. Medical tests required
under the emergency section of the medical surveillance section (M)(4)
must be conducted.
If the chemical is swallowed do not induce vomiting but remove by
gastric lavage.
Appendix D to Sec. 1910.1050--Sampling and Analytical Methods for MDA
Monitoring and Measurement Procedures
Measurements taken for the purpose of determining employee exposure
to MDA are best taken so that the representative average 8-hour exposure
may be determined from a single 8-hour sample or two (2) 4-hour samples.
Short-time interval samples (or grab samples) may also be used to
determine average exposure level if a minimum of five measurements are
taken in a random manner over the 8-hour work shift. Random sampling
means that any portion of the work shift has the same chance of being
sampled as any other. The arithmetic average of all such random samples
taken on one work shift is an estimate of an employee's average level of
exposure for that work shift. Air samples should be taken in the
employee's breathing zone (air that would most nearly represent that
inhaled by the employee).
There are a number of methods available for monitoring employee
exposures to MDA. The method OSHA currently uses is included below.
The employer, however, has the obligation of selecting any
monitoring method which meets the accuracy and precision requirements of
the standard under his unique field conditions. The standard requires
that the method of monitoring must have an accuracy, to a 95 percent
confidence level, of not less than plus or minus 25 percent for the
select PEL.
OSHA Methodology
Sampling Procedure
Apparatus
Samples are collected by use of a personal sampling pump that can be
calibrated within 5% of the recommended flow rate with the
sampling filter in line.
Samples are collected on 37 mm Gelman type A/E glass fiber filters
treated with sulfuric acid. The filters are prepared by soaking each
filter with 0.5 mL of 0.26N H2 SO4. (0.26 N
H2 SO4 can be prepared by diluting 1.5 mL of 36N
H2 SO4 to 200 mL with deionized water.) The
filters are dried in an oven at 100 degrees C for one hour and then
assembled into two-piece 37 mm polystyrene cassettes with backup pads.
The cassettes are sealed with shrink bands and the ends are plugged with
plastic plugs.
After sampling, the filters are carefully removed from the cassettes
and individually transferred to small vials containing approximately 2
mL deionized water. The vials
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must be tightly sealed. The water can be added before or after the
filters are transferred. The vials must be sealable and capable of
holding at least 7 mL of liquid. Small glass scintillation vials with
caps containing Teflon liners are recommended.
Reagents
Deionized water is needed for addition to the vials.
Sampling Technique
Immediately before sampling, remove the plastic plugs from the
filter cassettes.
Attach the cassette to the sampling pump with flexible tubing and
place the cassette in the employee's breathing zone.
After sampling, seal the cassettes with plastic plugs until the
filters are transferred to the vials containing deionized water.
At some convenient time within 10 hours of sampling, transfer the
sample filters to vials.
Seal the small vials lengthwise.
Submit at least one blank filter with each sample set. Blanks should
be handled in the same manner as samples, but no air is drawn through
them.
Record sample volumes (in L of air) for each sample, along with any
potential interferences.
Retention Efficiency
A retention efficiency study was performed by drawing 100 L of air
(80% relative humidity) at 1 L/min through sample filters that had been
spiked with 0.814 [mu]g MDA. Instead of using backup pads, blank acid-
treated filters were used as backups in each cassette. Upon analysis,
the top filters were found to have an average of 91.8% of the spiked
amount. There was no MDA found on the bottom filters, so the amount lost
was probably due to the slight instability of the MDA salt.
Extraction Efficiency
The average extraction efficiency for six filters spiked at the
target concentration is 99.6%.
The stability of extracted and derivatized samples was verified by
reanalyzing the above six samples the next day using fresh standards.
The average extraction efficiency for the reanalyzed samples is 98.7%.
Recommended Air Volume and Sampling Rate
The recommended air volume is 100 L.
The recommended sampling rate is 1 L/min.
Interferences (Sampling)
MDI appears to be a positive interference. It was found that when
MDI was spiked onto an acid-treated filter, the MDI converted to MDA
after air was drawn through it.
Suspected interferences should be reported to the laboratory with
submitted samples.
Safety Precautions (Sampling)
Attach the sampling equipment to the employees so that it will not
interfere with work performance or safety.
Follow all safety procedures that apply to the work area being
sampled.
Analytical Procedure
Apparatus: The following are required for analysis.
A GC equipped with an electron capture detector. For this evaluation
a Tracor 222 Gas Chromatograph equipped with a Nickel 63 High
Temperature Electron Capture Detector and a Linearizer was used.
A GC column capable of separating the MDA derivative from the
solvent and interferences. A 6 ft x 2 mm ID glass column packed with 3%
OV-101 coated on 100/120 Gas Chrom Q was used in this evaluation.
A electronic integrator or some other suitable means of measuring
peak areas or heights.
Small resealable vials with Teflon-lined caps capable of holding 4
mL.
A dispenser or pipet for toluene capable of delivering 2.0 mL.
Pipets (or repipets with plastic or Teflon tips) capable of
delivering 1 mL for the sodium hydroxide and buffer solutions.
A repipet capable of delivering 25 [mu]L HFAA.
Syringes for preparation of standards and injection of standards and
samples into a GC.
Volumetric flasks and pipets to dilute the pure MDA in preparation
of standards.
Disposable pipets to transfer the toluene layers after the samples
are extracted.
Reagents
0.5 NaOH prepared from reagent grade NaOH.
Toluene, pesticide grade. Burdick and Jackson distilled in glass
toluene was used.
Heptafluorobutyric acid anhydride (HFAA). HFAA from Pierce Chemical
Company was used.
pH 7.0 phosphate buffer, prepared from 136 g potassium dihydrogen
phosphate and 1 L deionized water. The pH is adjusted to 7.0 with
saturated sodium hydroxide solution.
4,4' -Methylenedianiline (MDA), reagent grade.
Standard Preparation
Concentrated stock standards are prepared by diluting pure MDA with
toluene. Analytical standards are prepared by injecting uL amounts of
diluted stock standards into vials that contain 2.0 mL toluene.
[[Page 397]]
25 uL HFAA are added to each vial and the vials are capped and
shaken for 10 seconds.
After 10 min, 1 mL of buffer is added to each vial.
The vials are recapped and shaken for 10 seconds.
After allowing the layers to separate, aliquots of the toluene
(upper) layers are removed with a syringe and analyzed by GC.
Analytical standard concentrations should bracket sample
concentrations. Thus, if samples fall out of the range of prepared
standards, additional standards must be prepared to ascertain detector
response.
Sample Preparation
The sample filters are received in vials containing deionized water.
1 mL of 0.5N NaOH and 2.0 mL toluene are added to each vial.
The vials are recapped and shaken for 10 min.
After allowing the layers to separate, approximately 1 mL aliquots
of the toluene (upper) layers are transferred to separate vials with
clean disposable pipets.
The toluene layers are treated and analyzed.
Analysis
GC conditions
Zone temperatures:
Column--220 degrees C
Injector--235 degrees C
Detector--335 degrees C
Gas flows, Ar/CH4 Column--28 mL/min
(95/5) Purge--40 mL/min
Injection volume: 5.0 uL
Column: 6 ft x 1/8 in ID glass, 3% OV-101 on 100/120 Gas Chrom Q
Retention time of MDA derivative: 3.5 min
Chromatogram
Peak areas or heights are measured by an integrator or other
suitable means.
A calibration curve is constructed by plotting response (peak areas
or heights) of standard injections versus ug of MDA per sample. Sample
concentrations must be bracketed by standards.
Interferences (Analytical)
Any compound that gives an electron capture detector response and
has the same general retention time as the HFAA derivative of MDA is a
potential interference. Suspected interferences reported to the
laboratory with submitted samples by the industrial hygienist must be
considered before samples are derivatized.
GC parameters may be changed to possibly circumvent interferences.
Retention time on a single column is not considered proof of
chemical identity. Analyte identity should be confirmed by GC/MS if
possible.
Calculations
The analyte concentration for samples is obtained from the
calibration curve in terms of ug MDA per sample. The extraction
efficiency is 100%. If any MDA is found on the blank, that amount is
subtracted from the sample amounts. The air concentrations are
calculated using the following formulae.
[mu]g/m\3\=([mu]g MDA per sample) (1000)/(L of air sampled)
ppb=([mu]g/m\3\) (24.46)/(198.3)=([mu]g/m\3\) (0.1233) where 24.46 is
the molar volume at 25 degrees C and 760 mm Hg
Safety Precautions (Analytical)
Avoid skin contact and inhalation of all chemicals.
Restrict the use of all chemicals to a fume hood if possible.
Wear safety glasses and a lab coat at all times while in the lab
area.
[57 FR 35666, Aug. 10, 1992, as amended at 57 FR 49649, Nov. 3, 1992; 61
FR 5508, Feb. 13, 1996; 63 FR 1293, Jan. 8, 1998; 67 FR 67965, Nov. 7,
2002]