Introduction

The National Occupational Exposure Survey (NOES), conducted by the National Institute for Occupational Safety and Health (NIOSH) from 1981 to 1983, estimated that 688,110 workers employed at 49,025 plant sites were potentially exposed to tetrachloroethylene in the U.S. during this period.

The NOES database does not contain information on the frequency, concentration, or duration of exposure; the survey provides only estimates of workers potentially exposed to chemicals in the workplace (US Environmental Protection Agency 1985).

Worker Exposure

A NIOSH survey of 44 dry-cleaning facilities reported time-weighted average (TWA, see explanation in Table 1) exposures to machine operators ranging from four ppm to 149 ppm. Much higher tetrachloroethylene levels are associated with cleaning spills or replacing dry-cleaning filters (Centers for Disease Control 1983).

Increased potential for exposure may also be encountered by the following workers:

• those performing degreasing and metal cleaning,
• plastic extruders,
• electronic assemblers,
• workers manufacturing tetrachloroethylene-containing consumer, and products (Blair 1980; Materna 1985; Solet, Robins et al. 1990).

Commercial Uses

Exposures to consumer products containing tetrachloroethylene have led to acute toxicity.

Accidental ingestions or spills, and use of products in small, enclosed spaces, may place unsuspecting persons at risk. For example, a spot remover containing tetrachloroethylene, used to clean a carpet in a poorly ventilated area, can produce dangerously high levels of the chemical in the air.

Dry Cleaning Hazards

Clothes, drapes, and other dry-cleaned fabrics may serve as a source of tetrachloroethylene release. One study found that newly dry-cleaned garments stored in a residential closet resulted in tetrachloroethylene levels of 0.5 - 2.9 milligrams per cubic meter (mg/m³) (74 - 428 ppb) in the closet after one day. Initial “airing out” of the clothes for four to eight hours had little effect on the resulting emissions (Tichenor, Sparks et al. 1990).

In one report, a 53-year-old male dry cleaner died after being overcome by tetrachloroethylene fumes (Levine, Fierro et al. 1981).A 2-year-old boy found dead 1.5 hours after he was placed in his room with curtains that had been incorrectly dry cleaned in a coin-operated dry cleaning machine (Garnier, Bedouin et al. 1996).

Indoor Air

Elevated indoor air levels may result from dry-cleaned fabrics. Other possible sources include “take home” contamination from exposed workers and contaminated water. Indoor air of exposed dry-cleaner workers' homes can contain levels of tetrachloroethylene nearly 10 times higher than the homes of nonexposed workers (Aggazzotti, Fantuzzi et al. 1994).

Contaminated water used for bathing and laundering can emit vapors that increase indoor air levels of tetrachloroethylene.

Maternal Transmission

Data from animal and human studies indicate that tetrachloroethylene crosses the placenta. Although the effects are uncertain, this ease of distribution may place the fetus at increased risk (van der Gulden and Zielhuis 1989; Fredriksson, Danielsson et al. 1993).In addition, tetrachloroethylene, like most other chlorinated chemicals, can be transmitted in breast milk, thus subjecting the nursing newborn to prolonged exposure.

In one case report, a nursing mother was repeatedly exposed to tetrachloroethylene fumes during lunch-hour visits with her husband at a dry-cleaning plant. She had tetrachloroethylene levels of 300 micrograms per deciliter (μg/dL) in blood and 1,000 μg/dL in breast milk. The nursing infant developed obstructive jaundice, possibly as a result of tetrachloroethylene exposure (Bagnell and Ellenberger 1977).

Progress Check