Disclaimer: The information contained in these
guidelines is intended for reference purposes only. It provides a
summary of information about chemicals that workers may be
exposed to in their workplaces. The information may be superseded by new developments in
the field of industrial hygiene. Readers are therefore advised to
regard these recomendations as general guidelines and to
determine whether new information is available.
OCCUPATIONAL SAFETY AND HEALTH GUIDELINE FOR XYLENE
INTRODUCTION
This guideline summarizes pertinent information about xylene for
workers and employers as well as for physicians, industrial
hygienists, and other occupational safety and health professionals
who may need such information to conduct effective occupational
safety and health programs. Recommendations may be superseded by new
developments in these fields; readers are therefore advised to regard
these recommendations as general guidelines and to determine
periodically whether new information is available.
SUBSTANCE IDENTIFICATION
* Formula
C(6)H(4)(CH(3))(2)
* Structure
(For Structure, see paper copy)
* Synonyms
Dimethyl benzene; xylol; methyl toluene; 1,4-dimethyl-benzene;
Violet 3.
* Identifiers
1. CAS 1330-20-7.
2. RTECS ZE2100000.
3. DOT UN: 1307 27.
4. DOT label: Flammable Liquid.
* Appearance and odor
The xylene in commercial use is composed of a mixture of the
three isomers ortho-xylene, meta-xylene, and para-xylene;
the meta isomer predominates in these mixtures. o-Xylene
and m-xylene are clear, colorless, flammable liquids that
have characteristically sweet, balsam-like odors. At low
temperatures, the para-isomer occurs in the form of clear,
colorless plates.
CHEMICAL AND PHYSICAL PROPERTIES
* Physical data
1. Molecular weight: 106.
2. Boiling point (760 torr): 135 to 145 degrees C (275 to 293
degrees F).
3. Specific gravity (water = 1): 0.86 at 20 degrees C (68
degrees F).
4. Vapor density (air = 1 at boiling point of xylene): 3.7.
5. Melting point: -25 degrees C (-13 degrees F).
6. Vapor pressure at 20 degrees C (68 degrees F): 7 to 9 torr.
7. Solubility: Insoluble in water; soluble in alcohol, ether,
acetone, and benzene.
8. Evaporation rate (butyl acetate = 1): 0.6.
* Reactivity
1. Conditions contributing to instability: Heat, sparks, or
open flame.
2. Incompatibilities: Contact of xylene with strong oxidizers
may cause fires and explosions.
3. Hazardous decomposition products: Toxic gases (such as
carbon monoxide) may be released in a fire involving xylene.
4. Special precautions: Xylene attacks some coatings and some
forms of plastic and rubber.
* Flammability
The National Fire Protection Association has assigned a
flammability rating of 3 (severe fire hazard) to xylene.
1. Flash point: 27 to 32 degrees C (81 to 90 degrees F).
2. Autoignition temperature: 464 degrees C (867 degrees F).
3. Flammable limits in air (percent by volume): Lower, 1;
upper, 7.
4. Extinguishant: Use foam, dry chemical, or carbon dioxide to
fight fires involving xylene. Water may be used to reduce
the rate of burning or to cool fire-exposed containers.
Fires involving xylene should be fought upwind and from the
maximum distance possible. Keep unnecessary people away;
isolate hazard area and deny entry. Emergency personnel
should stay out of low areas and ventilate closed spaces
before entering. Vapor explosion and poison hazards may
occur indoors, outdoors, or in sewers. Vapors may travel to
a source of ignition and flash back. Containers of xylene
may explode in the heat of the fire and should be moved from
the fire area if it is possible to do so safely. If this is
not possible, cool containers from the sides with water
until well after the fire is out. Stay away from the ends
of containers. Personnel should withdraw immediately if a
rising sound from a venting safety device is heard or if
there is discolora-tion of a container due to fire. Dikes
should be used to contain fire-control water for later
disposal. If a tank car or truck is involved in a fire,
personnel should isolate an area of a half a mile in all
directions. Firefighters should wear a full set of
protective clothing, including a self-contained breathing
apparatus, when fighting fires involving xylene.
Firefighters' protective clothing may provide limited
protection against fires involving xylene.
* Warning properties
The odor threshold for xylene is 1 part per million (ppm)
parts of air. Because this value is below the Occupational
Safety and Health Administration (OSHA) current permissible
exposure limit (PEL) of 100 ppm [29 CFR 1910.1000, Table
Z-1-A], xylene is considered to have adequate warning
properties.
* Eye irritation properties
The eye irritation threshold for xylene is 200 ppm
(870 mg/m(3)).
EXPOSURE LIMITS
The current OSHA PEL for xylene is 100 ppm (435 milligrams per cubic
meter (mg/m(3)) of air) as an 8-hour time-weighted average (TWA)
concentration and 150 ppm (655 mg/m(3)) as a 15-minute TWA short-term
exposure limit (STEL). A STEL is the maximum 15-minute concentration
to which workers may be exposed during any 15-minute period of the
working day [29 CFR 1910.1000, Table Z-1-A]. The National Institute
for Occupational Safety and Health (NIOSH) recommended exposure
limits (RELs) for xylene are 100 ppm (435 mg/m(3)) as a TWA for up to
a 10-hour workshift and a 40-hour workweek and 200 ppm (868 mg/m(3))
for 10 minutes as a short-term limit [NIOSH Recommendations, 1988].
The American Conference of Governmental Industrial Hygienists (ACGIH)
has assigned xylene a threshold limit value (TLV) of 100 ppm (435
mg/m(3)) as a TWA for a normal 8-hour workday and a 40-hour workweek
and a short-term exposure limit (STEL) of 150 ppm (655 mg/m(3)) for
periods not to exceed 15 minutes [ACGIH 1988, p. 42]. The OSHA and
ACGIH limits are based on the risk of irritant, narcotic, and chronic
effects associated with exposure to xylene, and the NIOSH limit is
based on xylene's potential to cause central nervous system
depression and respiratory irritation.
HEALTH HAZARD INFORMATION
* Routes of exposure
Exposure to xylene can occur via inhalation, ingestion, eye
or skin contact, and, to a small extent, by absorption
through the skin.
* Summary of toxicology
1. Effects on Animals: Xylene exposure produces central
nervous system depression and irritation of the eyes and
skin in animals. Xylene is also fetotoxic and teratogenic
in several species of experimental animals when administered
by the oral or inhalation routes [RTECS 1989]. The LC(50)
in the rat for a 4-hour xylene inhalation exposure is
5000 ppm, and the oral LD(50) in the same species is
4300 mg/kg [RTECS 1989]. The meta isomer may be more
acutely toxic than the o- or p-isomer: mice exposed for
24 hours to 2010 ppm of the m-isomer or to 3062 ppm of the
o-isomer died, while exposure for the same period to
4912 ppm of the p-isomer did not cause death [Proctor,
Hughes, and Fischman 1988, p. 511]. Rats exposed to a
1600-ppm concentration of xylene (isomer unspecified) for 2 or
4 days showed signs of irritation, became uncoor-dinated,
lost weight, had an increased red blood cell count,
exhibited signs of narcosis, and died [Proctor, Hughes, and
Fischman 1988, p. 511]. Rats exposed to a 980-ppm
concentration of xylene for 7 days developed leukopenia, and
autopsy revealed kidney congestion and hyperplasia of the
bone marrow and spleen [Proctor, Hughes, and Fischman 1988,
p. 511]. In contact with the eye, xylene causes irritation
of the conjunctiva, tur-bidity of the cornea, swelling, and
tearing in rabbits [Clayton and Clayton 1981, p. 3292].
Repeated application to rabbit skin of a 95- or 100-percent
solution of xylene causes redness, moderate irritation, and
slight necrosis [Proctor, Hughes, and Fischman 1988, p. 511;
RTECS 1989]. Rabbits exposed for 40 to 55 days to a xylene
concentra-tion of 1150 ppm developed a decrease in their red
and white blood cell counts and an increase in thrombocytes,
but these effects were reversible [Proctor, Hughes, and
Fischman 1988, p. 571]. In chronic inhalation studies, rats
and dogs exposed to 800 ppm for 6 hours/day for 65 days
showed no measurable ill effects [ACGIH 1986, p. 637]. No
signs of carcinogenicity were noted in long-term gavage
studies in rats and mice [Proctor, Hughes, and Fischman
1988, p. 511]. Administered subcutaneously to rats at
300 mg/kg/day for 6 weeks or at 700 mg/kg/day for 9 weeks,
xylene failed to cause hematopoietic effects; earlier
reports of xylene's myelotoxicity appear to have been based
on exposures to xylene contaminated with benzene, a known
myelotoxin [HSDB 1986; ACGIH 1986, p. 637]. The offspring
of pregnant rats inhaling 50 mg/m(3) xylene for 6 hours on
days 1 to 21 of pregnancy or 250 or 600 mg/m(3) for 24 hours
on days 7 to 15 of pregnancy had an increased incidence of
musculoskeletal abnormalities, and the offspring of pregnant
mice administered xylene by inhalation or oral dosing also
showed developmental abnormalities [RTECS 1989].
2. Effects on Humans: Xylene is an irritant of the eyes and
mucous membranes at concentrations below 200 ppm, and it is
narcotic at high concentrations [AIHA 1978; Proctor, Hughes,
and Fischman 1988, p. 511]. The estimated oral LD(50) for
humans is 50 mg/kg [EPA Health Advisory, 1987, p. 4]. Of
three workers exposed to xylene concentrations of
approximately 10,000 ppm for 18.5 hours, one died and two
recovered slowly after a period of unconsciousness and
retrograde amnesia; disturbances of liver and kidney
function were noted in these workers [ACGIH 1986, p. 637;
Baselt 1980, p. 286; Clayton and Clayton 1981, p. 3292].
Ingestion of xylene causes gastrointestinal distress and may
cause toxic hepatitis [Clayton and Clayton 1981, p. 3294].
Aspiration of xylene or acute exposure to high vapor
concentrations of this substance may cause chemical
pneumonitis, hemorrhage into the air spaces, and pulmonary
edema [Clayton and Clayton 1981, p. 3294; Klaassen, Amdur,
and Doull 1986, p. 351]. A worker exposed to the vapors of
a solvent containing 75 percent xylene (approximate airborne
xylene concentration of 60 to 350 ppm) developed giddiness,
anorexia, and vomiting [Proctor, Hughes, and Fischman 1988,
p. 511]. After inhalation of high (not further specified)
concentrations of xylene, workers may become flushed, feel
hot, and experience confusion, dizziness, tremors, and other
signs or symptoms of central nervous system toxicity
[Clayton and Clayton 1981, p. 3294]. Blood dyscrasias that
have proven fatal in at least one case are reported to have
been the result of chronic xylene exposure, but these
hematopoietic effects are now believed to have been caused
by benzene, formerly a common contaminant of xylene [ACGIH
1986, p. 637]. Chronic exposure to xylene may cause central
nervous system depression, anemia, mucosal hemorrhage, bone
marrow hyperplasia, liver enlargement, liver necrosis, and
nephrosis [Clayton and Clayton 1981, p. 3295]. Repeated
contact of the skin with xylene causes drying and dermatitis
[Clayton and Clayton 1981, p. 3295].
* Signs and symptoms of exposure
1. Acute exposure: The signs and symptoms of acute exposure to
xylene include headache, fatigue, irritability, lassitude,
nausea, anorexia, flatulence, irritation of the eyes, nose,
and throat, and motor incoordination and impairment of
equilibrium. Flushing, redness of the face, a sensation of
increased body heat, increased salivation, tremors,
dizziness, confusion, and cardiac irritability have also
been reported.
2. Chronic exposure: The signs and symptoms of chronic
exposure to xylene may include conjunctivitis; dryness of
the nose, throat, and skin; dermatitis; and kidney and liver
damage.
* Emergency procedures:
In the event of an emergency, remove the victim from further
exposure, send for medical assistance, and initiate the
following emergency procedures:
1. Eye exposure: If xylene or a solution containing xylene
gets into the eyes, immediately flush the eyes with large
amounts of water for a minimum of 15 minutes, lifting the
lower and upper lids occasionally. Get medical attention as
soon as possible.
2. Skin exposure: If xylene or a solution containing xylene
contacts the skin, the contaminated skin should be washed
with soap and water. If irritation persists, get medical
attention.
3. Inhalation: If xylene vapors are inhaled, move the victim
at once to fresh air and get medical care as soon as
possible. If the victim is not breathing, perform
cardiopulmonary resuscitation; if breathing is difficult,
give oxygen. Keep the victim warm and quiet until medical
help arrives.
4. Ingestion: DO NOT INDUCE VOMITING. If xylene or a solution
containing xylene is ingested, give the victim several
glasses of water to drink. Get medical help immediately.
Keep the victim warm and quiet until medical help arrives.
5. Rescue: Remove an incapacitated worker from further
exposure and implement appropriate emergency procedures
(e.g., those listed on the Material Safety Data Sheet
required by OSHA's Hazard Communication Standard, 29 CFR
1910.1200). All workers should be familiar with emergency
procedures and the location and proper use of emergency
equipment.
EXPOSURE SOURCES AND CONTROL METHODS
The following operations may involve xylene and lead to worker
exposures to this substance:
- Blending of motor and aviation fuels
- Use as a diluent or solvent in lacquers, varnishes, inks,
paints, surface coatings, dyes, adhesives, cleaning fluids,
and rubber cements
- Use as a feedstock for xylidenes, benzoic acid, phthalic
anhydride, and isophthalic and terephthalic acids and their
esters
- Manufacture of quartz crystal oscillators, hydrogen
peroxide, perfumes, insect repellents, dyes,
pharmaceuticals, vitamins, and leather, and use as a
sterilizing agent for cat-gut
- Formulation of insecticides
- Use with Canada balsam as oil-immersion fluid in microscopy
and as a cleaning agent in laboratory applications
Methods that are effective in controlling worker exposures to xylene,
depending on the feasibility of implementation, are
- Process enclosure,
- Local exhaust ventilation,
- General dilution ventilation, and
- Personal protective equipment.
The following publications are good sources of information on control
methods:
1. ACGIH [1986]. Industrial ventilation--a manual of
recommended practice. Cincinnati, OH: American Conference
of Governmental Industrial Hygienists.
2. Burton DJ [1986]. Industrial ventilation--a self study
companion. Cincinnati, OH: American Conference of
Governmental Industrial Hygienists.
3. Alden JL, Kane JM [1982]. Design of industrial ventilation
systems. New York, NY: Industrial Press, Inc.
4. Wadden RA, Scheff PA [1987]. Engineering design for control
of workplace hazards. New York, NY: McGraw-Hill.
5. Plog BA [1988]. Fundamentals of industrial hygiene.
Chicago, IL: National Safety Council.
MEDICAL MONITORING
Workers who may be exposed to chemical hazards should be monitored in
a systematic program of medical surveillance that is intended to
prevent occupational injury and disease. The program should include
education of employers and workers about work-related hazards,
placement of workers in jobs that do not jeopardize their safety or
health, early detection of adverse health effects, and referral of
workers for diagnosis and treatment. The occurrence of disease or
other work-related adverse health effects should prompt immediate
evaluation of primary preventive measures (e.g., indus-trial hygiene
monitoring, engineering controls, and personal protective equipment).
A medical monitoring program is intended to supplement, not replace,
such measures. To place workers effectively and to detect and
control work-related health effects, medical evaluations should be
performed (1) before job placement, (2) periodically during the
period of employment, and (3) at the time of job transfer or
termination.
* Preplacement medical evaluation
Before a worker is placed in a job with a potential for
exposure to xylene, the examining physician should evaluate
and document the worker's baseline health status with
thorough medical, environmental, and occupational histories,
a physical examination, and physiologic and laboratory tests
appropriate for the anticipated occupational risks. These
should concentrate on the function and integrity of the
central nervous system, blood, liver, kidneys, and skin.
A preplacement medical evaluation is recommended to assess
an individual's suitability for employment at a specific job
and to detect and assess medical conditions that may be
aggravated or may result in increased risk when a worker is
exposed to xylene at or below the prescribed exposure limit.
The examining physician should consider the probable
frequency, intensity, and duration of exposure as well as
the nature and degree of any applicable medical condition.
Such conditions (which should not be regarded as absolute
contraindications to job placement) include a history and
other findings consistent with diseases of the central
nervous system, blood, liver, kidneys, or skin.
* Periodic medical examinations and biological monitoring
Occupational health interviews and physical examinations
should be performed at regular intervals during the
employment period, as mandated by any applicable Federal,
State, or local standard. Where no standard exists and the
hazard is minimal, evaluations should be conducted every 3
to 5 years or as frequently as recommended by an experienced
occupational health physician. Additional examinations may
be necessary if a worker develops symptoms attributable to
xylene exposure. The interviews, examinations, and medical
screening tests should focus on identifying the adverse
effects of xylene on the central nervous system, blood,
liver, kidneys, or skin. Current health status should be
compared with the baseline health status of the individual
worker or with expected values for a suitable reference
population.
Biological monitoring involves sampling and analyzing body
tissues or fluids to provide an index of exposure to a toxic
substance or metabolite. Xylene can be detected in the
end-exhaled air, venous blood, and urine of exposed individuals.
However, urinary levels of methylhippuric acid, a metabolite
of xylene, appear to correlate better with airborne xylene
concentrations than blood or breath concentrations of
xylene. Some sources report that a urinary concentration of
1.5 gram methyl-hippuric acid per gram creatinine in urine
correlates with an 8-hour exposure to an airborne
concentration of 100 ppm xylene and a moderate level of work
activity.
* Medical examinations recommended at the time of job transfer
or termination
The medical, environmental, and occupational history
interviews, the physical examination, and selected
physiologic or laboratory tests that were conducted at the
time of placement should be repeated at the time of job
transfer or termination to determine the worker's medical
status at the end of his or her employment. Any changes in
the worker's health status should be compared with those
expected for a suitable reference population. Because
occupational exposure to xylene may cause diseases with
prolonged latent periods, the need for medical monitoring
may extend well beyond the termination of employment.
WORKPLACE MONITORING AND MEASUREMENT PROCEDURES
Determination of a worker's exposure to airborne xylene is made using
a charcoal tube (100/50 mg sections, 20/40 mesh). Samples are
collected at a maximum flow rate of 0.2 liter per minute until a
maximum air volume of 12 liters is collected. The sample is then
treated with carbon disulfide to extract the xylene. Analysis is
conducted by gas chromatography using a flame ionization detector.
This method has a sampling and analytical error of 0.10 and is
included as NIOSH Method 1501 in the NIOSH Manual of Analytical
Methods, 3rd edition, Volume 2 [NIOSH 1984].
PERSONAL HYGIENE PROCEDURES
If xylene contacts the skin, workers should immediately wash the
affected areas with soap and water.
Clothing contaminated with xylene should be removed immediately, and
provisions should be made for the safe removal of the chemical from
the clothing. Persons laundering the clothes should be informed of
the hazardous properties of xylene, particularly its potential to
cause dryness and irritation of the skin.
A worker who handles xylene should thoroughly wash hands, forearms,
and face with soap and water before eating, using tobacco products,
or using toilet facilities.
Workers should not eat, drink, or use tobacco products in areas where
xylene is handled, processed, or stored.
STORAGE
Xylene should be stored in a cool, dry, well-ventilated area in
tightly sealed containers that are labeled in accordance with OSHA's
Hazard Communication Standard [29 CFR 1910.1200]. Outside or
detached storage is preferred; inside storage must be in a standard
flammable liquids storage room or cabinet. The ventilation used in
storage areas must be of explosion-proof design. Containers of
xylene should be protected from physical damage and should be stored
separately from strong oxidizers, heat, sparks, and open flame. Only
nonsparking tools may be used to handle xylene. To prevent static
sparks, containers must be grounded and bonded for transfers.
Because empty containers that formerly contained xylene may still
hold product residues, they should be handled appropriately.
SPILLS AND LEAKS
In the event of a spill or leak involving xylene, persons not wearing
protective equipment and clothing should be restricted from
contaminated areas until cleanup has been completed. The following
steps should be undertaken following a spill or leak:
1. Do not touch the spilled material; stop the leak if it is
possible to do so without risk.
2. Notify safety personnel.
3. Remove all sources of heat and ignition.
4. Ventilate potentially explosive atmospheres using maximally
explosion-proof equipment.
5. Use nonsparking tools for cleanup.
6. Water spray may be used to reduce vapors, but the spray may
not prevent ignition in closed spaces.
7. For small liquid spills, take up with sand or other
noncombustible absorbent material and place into closed
containers for later disposal.
8. For large liquid spills, build dikes far ahead of the spill
to contain the xylene for later reclamation or disposal.
EMERGENCY PLANNING, COMMUNITY RIGHT-TO-KNOW, AND HAZARDOUS WASTE
MANAGEMENT REQUIREMENTS
The Environmental Protection Agency's (EPA's) regulatory requirements
for emergency planning, community right-to-know, and hazardous waste
management may vary over time. Users are therefore advised to
determine periodically whether new information is available.
* Emergency planning requirements
Xylene is not subject to EPA emergency planning requirements
under the Superfund Amendments and Reauthorization Act
(Title III).
* Reportable quantity requirements (releases of hazardous
substances)
A hazardous substance release is defined by EPA as any
spilling, pumping, pouring, emitting, emptying, discharging,
injecting, escaping, leaching, dumping, or disposing into
the environment (including the abandonment or discarding of
containers) of hazardous substances. In the event of a
release that is above the reportable quantity for that
chemical, employers are required by the Comprehensive
Environmental Response, Compensation, and Liability Act
(CERCLA) to notify the proper Federal authorities.
The reportable quantity for xylene is 1000 pounds. If an
amount equal to or greater than this quantity is released
within a 24-hour period, CERCLA [40 CFR Part 302.6] requires
employers to notify the National Response Center IMMEDIATELY
at (800) 424-8802 (in Washington, D.C. at (202) 426-2675).
* Community right-to-know requirements
Employers who own or operate facilities in SIC codes 20-39
that employ 10 or more employees and that manufacture 25,000
pounds or more of xylene per calendar year or otherwise use
10,000 pounds or more of xylene per calendar year are
required by EPA (49 CFR Part 372.30) to submit a Toxic
Chemical Release Inventory form (Form R) to EPA reporting
the amount of xylene emitted or released from their facility
annually.
* Hazardous waste management requirements
EPA considers a waste to be hazardous if it exhibits any of
the following characteristics: ignitability, corrosivity,
reactivity, or toxicity, as defined in 40 CFR 261.21-261.24.
Under the Resource Conservation and Recovery Act (RCRA), EPA
has specifically listed many chemical wastes as hazardous.
Xylene is listed as a hazardous waste under RCRA and has
been assigned EPA Hazardous Waste No. U239. It is approved
for land disposal as long as the concentration of xylene in
the waste or treatment residual does not exceed 28 mg/kg.
Xylene also may be disposed of in an organometallic or
organic lab pack that meets the requirements of 40 CFR
264.316 or 265.316.
Providing more information about the removal and disposal of
specific chemicals is beyond the scope of this guideline.
EPA, U.S. Department of Transportation, and State and local
regulations should be followed to ensure that removal,
transport, and disposal of this substance are conducted in
accordance with existing regulations. To be certain that
chemical waste disposal meets EPA regulatory requirements,
employers should address any questions to the RCRA hotline
at (202) 382-3000 (in Washington, D.C.) or toll-free at
(800) 424-9346 (outside Washington, D.C.). In addition,
relevant State and local authorities should be contacted for
information on any requirements they may have for the waste
removal and disposal of this substance.
RESPIRATORY PROTECTION
* Conditions for respirator use
Good industrial hygiene practice requires that engineering
controls be used where feasible to reduce workplace
concentrations of hazardous materials to the prescribed
exposure limit. However, some situations may require the
use of respirators to control exposure. Respirators must be
worn if the ambient concentration of xylene exceeds
prescribed exposure limits. Respirators may be used
(1) before engineering controls have been installed,
(2) during work operations such as maintenance or repair
activities that involve unknown exposures, (3) during
operations that require entry into tanks or closed vessels,
and (4) during emergency situations. If the use of
respirators is necessary, the only respirators permitted are
those that have been approved by NIOSH and the Mine Safety
and Health Administration (MSHA).
* Respiratory protection program
Employers should institute a complete respiratory protection
program that, at a minimum, complies with the requirements
of OSHA's Respiratory Protection Standard [29 CFR 1910.134].
Such a program must include respirator selection (see Table
1), an evaluation of the worker's ability to perform the
work while wearing a respirator, the regular training of
personnel, fit testing, periodic workplace monitoring, and
regular respirator maintenance, inspection, and cleaning.
The implementation of an adequate respiratory protection
program (including selection of the correct respirator)
requires that a knowledgeable person be in charge of the
program and that the program be evaluated regularly. For
additional information on the selection and use of
respirators and on the medical screening of respirator
users, consult the NIOSH Respirator Decision Logic
[NIOSH 1987c] and the NIOSH Guide to Industrial
Respiratory Protection [NIOSH 1987a].
Table 1 lists the respiratory protection that NIOSH
recommends for workers exposed to xylene. The recommended
protection may vary over time because of changes in the
exposure limit for xylene or in respirator certification
requirements. Users are therefore advised to determine
periodically whether new information is available.
PERSONAL PROTECTIVE EQUIPMENT
Protective clothing should be worn to prevent skin contact with
xylene. Impervious gloves, boots, aprons, gauntlets, and other
protective clothing are recommended for use as necessary [Genium MSDS
1988, No. 318]. Chemical protective clothing should be selected on
the basis of available performance data, manufacturers'
recommendations, and evaluation of the clothing under actual
conditions of use. The following materials have been recommended for
use against permeation by xylene and may provide protection for
periods greater than 8 hours: polyvinyl alcohol and Viton.
Materials that may withstand permeation for more than 4 but fewer
than 8 hours are Teflon and polyethylene/ethylene vinyl alcohol
[Forsberg and Mansdorf 1989, p. 46]. Natural rubber, butyl rubber,
neoprene, a nitrile rubber and polyvinyl chloride mixture, nitrile
rubber, polyethylene, polyvinyl chloride, and a neoprene and natural
rubber mixture have demonstrated poor resistance to permeation by
xylene [Schwope et al. 1987, p. 99; Forsberg and Mansdorf 1989, p.
46].
If xylene is dissolved in an organic solvent, the permeation
properties of both the solvent and the mixture must be considered
when selecting personal protective equipment and clothing.
Safety glasses, goggles, or faceshields should be worn during
operations in which xylene might contact the eyes (e.g., through
splashes of solution). Eyewash fountains and emergency showers
should be available within the immediate work area whenever the
potential exists for eye or skin contact with xylene. Contact lenses
should not be worn if the potential exists for xylene exposure
[NIOSH/OSHA Occupational Health Guideline 1981, p. 3; Genium MSDS
1988, No. 318].
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ACGIH [1986]. Documentation of the threshold limit values and
biological exposure indices. 5th edition. Cincinnati, OH: American
Conference of Governmental Industrial Hygienists.
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indices for 1988-1989. Cincinnati, OH: American Conference of
Governmental Industrial Hygienists.
AIHA [1978]. Hygienic guide series. Akron, OH: American Industrial
Hygiene Association.
Baselt RC [1980]. Biological monitoring methods for industrial
chemicals. Davis, CA: Biomedical Publications.
Clayton G, Clayton F [1981]. Patty's industrial hygiene and
toxicology. 3rd revised edition. New York, NY: John Wiley & Sons.
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Printing Office, Office of the Federal Register.
EPA Health Advisory [1987]. Xylenes. Washington, DC: Environmental
Protection Agency, Office of Drinking Water.
HSDB [1986]. Xylenes. Bethesda, MD: The Hazardous Substances Data
Bank, National Library of Medicine.
Klaassen CD, Amdur MO, Doull J [1986]. Casarett and Doull's
toxicology. 3rd edition. New York, NY: Macmillan Publishing
Company.
NIOSH [1984]. NIOSH manual of analytical methods. 3rd edition.
Cincinnati, OH: U.S. Department of Health, Education, and Welfare,
Public Health Service, Centers for Disease Control, National
Institute for Occupational Safety and Health.
NIOSH [1987a]. NIOSH guide to industrial respiratory protection.
Cincinnati, OH: U.S. Department of Health and Human Services, Public
Health Service, Centers for Disease Control, National Institute for
Occupational Safety and Health. DHHS (NIOSH) Publication No. 87-116.
NIOSH [1987b]. NIOSH pocket guide to chemical hazards. Cincinnati,
OH: U.S. Department of Health and Human Services, Public Health
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Table 1 Respiratory protection recommended by NIOSH for workers
exposed to xylene*
|
Condition |
Recommended respiratory protection** |
|
Airborne concentration of xylene: |
100 to 200(+) ppm (2 X REL) |
Any air-purifying, half mask
respirator (including a disposable
respirator) equipped with organic
vapor cartridges, or
Any supplied-air respirator
equipped with a half mask and
operated in a demand
(negative-pressure) mode, or
Any supplied-air respirator
equipped with a half mask and
operated in a pressure-demand or
other positive-pressure mode |
100 to 1000 ppm (10 X REL) |
Any air-purifying, full-facepiece
respirator equipped with organic
vapor cartridges or an organic
vapor canister, or
Any powered, air-purifying
respirator equipped with a
loose-fitting hood or helmet and
organic vapor cartridges or an organic
vapor canister, or
Any powered, air-purifying
respirator equipped with a
tight-fitting face-piece and organic
vapor cartridges or an organic
vapor canister, or
Any supplied-air respirator
equipped with a full facepiece and
operated in a demand
(negative-pressure) mode, or
Any supplied-air respirator
equipped with a hood or helmet and
operated in a continuous-flow mode,
or
Any supplied-air respirator
equipped with a tight-fitting
facepiece and operated in a
continuous-flow mode, or
Any supplied-air respirator
equipped with a full facepiece and
operated in a pressure-demand or
other positive-pressure mode, or
Respiratory protection recommended
by NIOSH for workers exposed to
xylene (continued)*
Any self-contained respirator
equipped with a full facepiece and
operated in a demand
(negative-pressure) mode |
Entry into IDLH(++) or unknown concentrations |
Any self-contained respirator equipped
with a full facepiece and operated
in a pressure-demand or other
positive-pressure mode, or
Any supplied-air respirator
equipped with a full facepiece and
operated in a pressure-demand or
other positive-pressure mode in
combina-tion with an auxiliary
self-contained breathing apparatus
operated in a pressure-demand or
other positive-pressure mode |
Firefighting |
Any self-contained respirator
equipped with a full facepiece and
operated in a pressure-demand or
other positive-pressure mode |
Escape |
Any air-purifying, full-facepiece
respirator equipped with an organic
vapor canister, or
Any escape-type, self-contained
breathing apparatus with a suitable
service life (number of minutes
required to escape the environment) |
|
The NIOSH REL is 100 ppm (435 mg/m(3)) as a TWA for up to a
10-hour workshift and a 40-hour workweek.
** Only NIOSH/MSHA-approved equipment should be used. Also,
note the following:
1. Respirators accepted for use at higher concentrations may be
used at lower concentrations; respirators must not, however,
be used at concentrations higher than those for which they
are approved.
2. Air-purifying respirators may not be used in
oxygen-deficient atmospheres or in airborne concentrations
that are immediately dangerous to life or health (IDLH).
(+) Only full-facepiece respirators should be used in
concentrations of xylene over 200 ppm because of its
irritant effects on the eyes.
(++) The xylene concentration that is immediately dangerous to
life and health (IDLH) is 1000 ppm [NIOSH 1987b].
|