Methylene Chloride (CAS# 75-09-2, also identified as dichloromethane or DCM), is a colorless liquid and a volatile chemical with a sweet odor. It has been used in a variety of consumer and commercial applications including adhesives, sealants, and automotive products. In a laboratory setting, DCM is commonly used in chemical processes such as general solvent use, chromatography, and organic syntheses.

Short-term exposure may cause dizziness, loss of consciousness, or death. Long term exposure may increase the risk of cancer or liver damage.

In April 2024, the Environmental Protection Agency (EPA) issued a new rule  under the Toxic Substance Control Act (TSCA) to address health risks associated with DCM, including neurotoxicity and cancer risks from inhalation and/or dermal exposure. Under this rule many consumer and commercial uses of DCM such as paint stripping, degreasing, adhesive removing etc. were prohibited. Laboratory use and waste disposal of DCM may continue only under certain specific restrictions and conditions. Additional information is available in EPA’s Fact Sheet.

Exposure Limits for DCM

• Action Level, 8-hour Time Weighted Average (TWA) - 1 ppm
• Existing Chemical Exposure Limit (ECEL), 8-hour TWA - 2 ppm
• Short Term Exposure Limit (STEL), 15-minute TWA - 16 ppm

Laboratory Use Conditions: Hierarchy of Controls
Among other use conditions, the rule requires that laboratories eliminate or reduce their use of DCM via substitution. Any remaining use of DCM must follow the hierarchy of controls below.

• Elimination: Reduce quantities of DCM where possible.
• Substitution: Use a less hazardous chemical where possible.
• Engineering Controls: Perform all activities using DCM inside a certified chemical fume hood, glove box, or other approved exposure control device.
• Store DCM in appropriate chemical storage cabinets, and collect DCM-containing waste in chemical fume hoods.
• Administrative Controls: Complete EH50: Halogenated Organic Solvents Safety Awareness  online training.
• Personal Protective Equipment (PPE): Wear the correct PPE (lab coat, safety glasses, and gloves) to help prevent workplace exposure.

Workplace Chemical Protection Program
View the DCM Workplace Chemical Protection Program (WCPP) here .

Facilities, Shops and Other Non-Laboratory Locations
University facilities and shops can use the following resources to find replacements for products containing DCM:

• The EPA has evaluated a list of alternative products  (Appendix A and B), which can be used to help find replacement products based on condition of use.
• More organic solvents are undergoing rulemaking  and may face similar restrictions as DCM in the future. The EPA Appendix B: Alternatives Calculator for Solvents can be filtered to specifically exclude these chemicals.