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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.


  1. Occupational Safety and Health Administration. OSHA safety and health standards. Washington, D.C.: Occupational Safety and Health Administration, 1980 (revised) (29 Code of Federal Regulations 1910.1000).

  2. National Institute for Occupational Safety and Health. Criteria for a recommended standard: occupational exposure to tetrachloroethylene (perchloroethylene). Cincinnati, Ohio.: National Institute for Occupational Safety and Health, 1976. (DHEW publication no. (NIOSH) 76-185).

  3. National Institute for Occupational Safety and Health. National occupational hazard survey. Cincinnati, Ohio: National Institute for Occupational Safety and Health, 1981.

  4. Perchloroethylene: chemical profile. Chemical Marketing Reporter 1979;216:9.

  5. Stewart RD, Gay HH, Erley DS, Hake CL, Schaffer AW. Human exposure to tetrachloroethylene vapor. Relationship of expired air and blood concentrations to exposure and toxicity. Arch Environ Health 1961;2:516-22.

  6. Stewart RD, Baretta ED, Dodd HC, Torkelson TR. Experimental human exposure to tetrachloroethylene. Arch Environ Health 1970;20:225-9.

  7. Carpenter CP. Chronic toxicity of tetrachloroethylene. J Indust Hyg Toxicol 1937;19:323-36.

  8. Coler HR, Rossmiller HR. Tetrachloroethylene exposure in small industry. Arch Indust Hyg 1953;8:227-33.

  9. Trense E, Zimmermann H. Lethal inhalation poisoning due to the chronic effects of tetrachloroethylene vapors. Zentralbl Arbeitsmed 1969;19:131-7.

  10. 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).

  11. 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.

  12. Stewart RD, Erley DS, Schaffer AW, Gay HH. Accidental vapor exposure to anesthetic concentrations of a solvent containing tetrachloroethylene. Indust Med Surg 1961;30:327-30.

  13. National Cancer Institute. Bioassay of tetrachloroethylene for possible carcinogenicity, 1977. Bethesda, Maryland: National Cancer Institute, 1977. (HEW publication no. (NIH) 77-813).

  14. 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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