Dichloromethane (DCM), also commonly called methylene chloride (CAS) 75-09-2, is a solvent used in industrial, commercial, and research applications. DCM can cause serious eye or skin irritation. 

In April 2024, The Environmental Protection Agency (EPA) issued a new rule under the Toxic Substance Control Act (TSCA) affecting the use of DCM, to protect human health from health risks such as neurotoxicity effects and cancer from inhalation and/or dermal exposures. Under this rule many consumer and commercial uses of DCM such as paint stripping, degreasing, adhesive removing etc. are prohibited. Laboratory use and waste disposal of DCM is allowed to continue under certain use restrictions and conditions. The EPA’s Fact Sheet contains more information. 

The EPA rule lowers previous regulatory exposure limits (see below), and requires rigorous hazard control and other strict safety measures. The EPA rule adds regulatory compliance requirements to existing Cal/OSHA requirements for DCM already in effect

Exposure Limits for DCM 

*This is the new lower exposure limit for regulatory compliance. 

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 EHS-1900 Chemical Safety in Labs and EHS-XXXX Working with DCM (Coming Soon) online training.
• Personal Protective Equipment (PPE): Wear the correct PPE (lab coat, safety glasses, and gloves) to help prevent workplace exposure. A flame resistant lab coat is recommended. Gloves should be Silver Shield, Viton, or PVA (except when working with aqueous solutions). 

Facilities, Shops and Other Non-Lab 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.
• N-Methylpyrrolidone (NMP), 1-Bromopropane (1-BP), 1,1,2-Trichloroethane (TCE), Perchloroethylene (PCE) 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.

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