Regulations (Preambles to Final Rules) - Table of Contents
• Record Type: Occupational Exposure to Methylene Chloride
• Section: 9
• Title: Section 9 - IX. Environmental Impact

IX. Environmental Impact

This section analyzes the impact on the environment of changing the standard for methylene chloride (MC) to an eight-hour time weighted average (TWA8) permissible exposure limit (PEL) of 25 parts per million (ppm), with a 125 ppm 15-minute short-term exposure limit (STEL) and ancillary requirements. It is based principally on information collected for OSHA by CONSAD Research Corporation and its subcontractor, PEI Associates Inc., and reported in Economic Analysis of Draft Regulatory Standard for Methylene Chloride, 1990, OSHA Docket, Ex. 15, and also draws upon other materials in the OSHA docket.

Current uses of methylene chloride involve releases to the air through venting of storage tanks or drums and through evaporation of MC during the performance of various activities such as paint stripping and cold cleaning indoors or outdoors. The volume of MC emitted as a percentage of MC used varies greatly among industries. Some processes, such as polyurethane foam manufacturing and paint stripping, typically release 100 percent of the MC to the atmosphere (Ex. 15). Other uses, such as solvent recovery and the manufacture of methylene chloride, involve less than 1 percent of the MC used being emitted to the atmosphere (Ex. 15). In addition, air, water, or solid waste pollution may occur as a result of the disposal of waste residues containing MC. Additional details by application group are presented in CONSAD's report [Ex. 15].

Future environmental releases of methylene chloride resulting from the final standard will largely be a function of how it affects the demand for methylene chloride and for its substitutes. The demand for methylene chloride has been declining (e.g., generally, it is no longer being used in formulating h