Carpet/4-Phenylcyclohexene Toxicity: The EPA Headquarters Case

At least 122 people were adversely affected by poor indoor air quality and fumes from new carpet installed at EPA headquarters from October 1987 through April 1988. Of these, 17 were unable to work at their normal duty stations, and at least 6 appear to have acquired multiple chemical sensitivity (MCS) as a result of exposure. Reports of similar phenomena from the public, structure-activity analyses, and exposure information indicate a causal relationship between MCS and exposure to 4-phenylcyclohexene (4-PC). Hypersensitivity can occur with exposure to carpet, glues or a combination of the two. Air monitoring for 4-PC and other agents was used to estimate levels of 4-PC that caused acute irritancy and acquisition of MCS. Application of safety factor methodology gives estimates likely to establish minimal levels of exposure against the phenomena. The source of 4-PC in carpet and glues and the means of lowering 4-PC in those products are discussed.