Uses of and exposure to trichloroethylene in U.S. industry: a systematic literature review.

This article describes a systematic review of the industrial hygiene literature for uses of trichloroethylene (TCE) in industry for the exposure assessment of two population-based case control studies of brain cancer in the United States. Papers and reports that address uses of and exposures to TCE were identified from MEDLINE, TOXLINE, NIOSHTIC, the NIOSH Health Hazard Evaluation database (keywords: chlorinated solvents and trichloroethylene), and in other reviews. This search was complemented by reviewing the reference lists from the identified literature. The collected information was systematized by the Standard Industrial Classification (SIC) system, and measurement data reported in the literature were summarized in a database. TCE use was extensive from the early 1920s through the 1970s mainly as a degreasing agent in metal-fabricating operations. After the 1970s it became less popular because of environmental concerns. TCE historically has had a multitude of uses in many other industries, e.g., dry cleaning, textile, electronics, leather, and rubber. Also, many products like adhesives, drugs, paints, inks, and various industrial products have contained TCE. It was banned as a food additive and in cosmetics in 1977. The arithmetic mean (AM) of the measurements across all industries and decades was 38.2 ppm. The highest personal and area air levels were reported in vapor degreasing (AM of 44.6 ppm). Most TCE measurements were performed in the 1950s, 1970s, and 1980s. The data described here could be used by exposure assessors as is to identify the presence and approximate levels of exposure. Using the same information as a basis should increase the reliability of the assessments, making it easier to compare both the exposure assessment methods and the epidemiologic results across different studies.