Worker Exposure to Perchloroethylene in Commercial Dry-
Cleaning Operations -- United States
Between 1977 and 1979, workers in commercial dry-cleaning
establishments were surveyed for exposure to vapors of the solvent,
perchloroethylene (PCE). Industrial hygienists collected samples
of
breathing-zone air from 144 of 353 workers employed at 44
commercial
dry-cleaning establishments: three in Cincinnati, seven in New York
City, eight in Detroit, nine in Chicago, and 17 in the San
Francisco
Bay area. Two types of air samples were collected: 1) long-term
samples, which measured the time-weighted-average (TWA) exposures
to
PCE over most of a work shift (including the time spent cleaning
and
handling textiles and working at front counters), and 2) short-term
(5- and 15-minute) samples, which measured exposures while
operators
transferred PCE-laden fabrics from washers to dryers, or performed
other duties (such as spot removal) involving heavy exposure to
PCE.
Exposures were compared by job classification (machine
operator,
presser, seamstress, and front-counter worker) and by the types of
machines used in the establishments. Two types of machines in
frequent use were: 1) separate units for washing and drying, which
require manual transfer of clothes from washer to dryer, and 2)
combined washer-dryer units, which do not require transfer.
Although exposures of most workers, especially those using
combined washer-dryer units, were low (Table 2), machine operators
who
transferred PCE-laden clothes from washers to dryers had relatively
high exposures. Machine operators at two of the 44 plants had 8-hr
TWA exposures to PCE exceeding the standard set by the Occupational
Safety and Health Administration (OSHA)*; workers in seven plants
had
peak exposures in excess of the OSHA limit. In nine of the 44
plants,
machine operators had exposures exceeding the TWA levels
recommended
by the National Institute for Occupational Safety and Health
(NIOSH)
on the basis of noncarcinogenic, toxic PCE effects**; workers in
seven
plants had 15-minute peak exposures in excess of the
NIOSH-recommended
levels. Of the operators using combined washer-dryer units, only
one
was exposed to PCE levels above the NIOSH-recommended TWA of 50
ppm;
none was exposed to peak levels above either the OSHA standard or
the
NIOSH-recommended level.
Reported by Industrywide Studies Br, Div of Surveillance, Hazard
Evaluations, and Field Studies, NIOSH, CDC.
Editorial Note
Editorial Note: An estimated 500,000 workers in 50,000 industrial
plants in the United States are exposed to PCE (3); over half the
300
million kilograms of PCE used annually are used in an estimated
25,000
dry-cleaning establishments (4). PCE vapor, at levels of 75-100
ppm,
is irritating to the eyes and upper respiratory tract (5,6); after
absorption, PCE is toxic to the liver and kidneys (7-9). At levels
of
100-280 ppm, PCE vapors affect the central nervous system, causing
headaches, lightheadedness, confusion, slurred speech, drowsiness,
reduced motor coordination, and memory impairment (5,6,9-11). Coma
and death can occur in persons exposed to levels greater than 2,000
ppm (7,12).
A toxicologic study published in 1977 by the National Cancer
Institute showed that oral ingestion of PCE in corn oil was
associated
with increased rates of liver carcinoma in mice (13). While humans
differ from animals in their susceptibility to specific chemicals,
substances causing cancer in experimental animals are considered
potential human carcinogens and should be treated as such in the
workplace. Therefore, in 1978, NIOSH recommended that PCE be
handled
in the workplace as a potential human carcinogen and that
occupational
exposure to it be reduced to the lowest possible limit (14).
Most dry-cleaning operations are small, often family owned and
operated. The average workforce in the 44 facilities surveyed here
numbered about seven; only four establishments had more than 12
employees. Due to the small workforce and low accident rate, dry
cleaners are not likely to be inspected by OSHA or by state and
local
agencies. Non-enforcement groups, such as the dry-cleaning trade
organizations and chemical suppliers, are available for
consultation
and assistance, but how often dry-cleaning owners or managers
consult
them for current occupational safety and health developments is
unknown.
The present study indicates that excessive PCE exposures were
not,
and probably are not now, pervasive in the dry-cleaning industry.
However, machine operators, many of whom are overexposed while
operating manual-transfer machines, receive the highest PCE
exposures. Substitution of less toxic solvents, engineering
redesign,
and/or substitution of machines could prevent excess exposure of
almost 4,000 operators. Further reductions could be achieved by
reengineering the combined machines, improving ventilation systems,
and/or using personal protective equipment. Even though most
dry-cleaning workers have exposures below the OSHA standards for
PCE,
the effects of low, chronic doses have not been adequately defined.
References
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health standards. Washington, D.C.: Occupational Safety and
Health Administration, 1980 (revised) (29 Code of Federal
Regulations 1910.1000).
National Institute for Occupational Safety and Health.
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for a recommended standard: occupational exposure to
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National Institute for Occupational Safety and Health, 1976.
(DHEW
publication no. (NIOSH) 76-185).
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Perchloroethylene: chemical profile. Chemical Marketing
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1979;216:9.
Stewart RD, Gay HH, Erley DS, Hake CL, Schaffer AW. Human
exposure to tetrachloroethylene vapor. Relationship of expired
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Stewart RD, Baretta ED, Dodd HC, Torkelson TR. Experimental
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exposure to tetrachloroethylene. Arch Environ Health
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Trense E, Zimmermann H. Lethal inhalation poisoning due to the
chronic effects of tetrachloroethylene vapors. Zentralbl
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Stewart RD, Hake CL, Forster HV, Lubrun AJ, Peterson JE, Wu A.
Tetrachloroethylene--development of a biologic standard for the
industrial worker by breath analysis. Milwaukee, Wisconsin:
The
Medical College of Wisconsin, 1974 (Report No.
NIOSH-MCOW-ENVM-PCE-74-6).
Rowe VK, McCollister DD, Spencer HC, Adams GM, Irish DD. Vapor
toxicity of tetrachloroethylene for laboratory animals and
human
subjects. Arch Indust Hyg 1952;5:566-79.
Stewart RD, Erley DS, Schaffer AW, Gay HH. Accidental vapor
exposure to anesthetic concentrations of a solvent containing
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National Cancer Institute. Bioassay of tetrachloroethylene for
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Cancer Institute, 1977. (HEW publication no. (NIH) 77-813).
National Institute for Occupational Safety and Health.
Tetrachloroethylene (perchloroethylene). Cincinnati, Ohio:
National Institute for Occupational Safety and Health, January
20,
1978. (NIOSH current intelligence bulletin 20; DHEW
publication
no. (NIOSH) 78-112).
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