In October 1998, OSHA issued a revised standard on methylene chloride. The UAW has pushed OSHA for over 10 years to pass a methylene chloride standard. The standard passed in 1997 set a maximum allowable exposure of 25 parts per million (ppm) (down from 500 ppm), but lacked protection from reprisals for reporting symptoms. The UAW sued OSHA to get more protective measures. The 8-hour Time Weighted Average (TWA) Permissible Exposure Limit (PEL) is 25 ppm. The Short Term Exposure Limit (STEL) is a 15-minute TWA of 125 ppm.
Exposure to methylene chloride has been shown to cause damage to the nervous system, heart, liver, and skin. Methylene chloride is used to clean metal and plastic, as a vehicle for adhesives, and in the manufacture of foamed plastics. Although the use of methylene chloride has been significantly reduced or even eliminated at many facilities over the years, exposure to methylene chloride vapors remains a health issue in the furniture and aircraft industries.