Background

Methylene chloride, also known as dichloromethane (DCM), is a common solvent used in a variety of consumer/commercial applications and is found in many academic research labs. The EPA determined that methylene chloride poses an “unreasonable risk to human health or the environment” following review under Toxic Substance Control Act (TSCA) regulations. The final rule was published in April 2024, which prohibits most consumer and commercial uses.

While this rule does not ban the use and handling of DCM in research laboratories, it does place DCM on EPA’s regulatory list.  An exemption for laboratory use is granted, provided that a workplace chemical protection program (WCPP) is developed.

What are the health risks?

Methylene chloride poses both non-cancer and cancer health risks from acute and chronic inhalation and dermal exposures. University staff exposure can increase the risk of developing cancer based on some animal studies, neurotoxicity effects (headaches, dizziness, etc.), heart and Liver damage, and skin or eye irritation. 

New Exposure Limits

The new EPA regulation severely reduced the exposure threshold relative to the OSHA standard (See Table 1). To put this in perspective, the odor threshold for methylene chloride is 250 parts per million (ppm), which is 125 times the new eight-hour time weighted average (TWA, 2 ppm). 

Compliance Timeline

EHRS Needs Your Help to Ensure Compliance with EPA and OSHA

1. If your lab or area has DCM that is no longer in use, please submit a Chemical Waste Pickup Request Form.  Please remove the DCM from the your chemical inventory to reflect its disposal.
2. If the lab or area is using DCM for applications prohibited by the TSCA final rule (e.g. paint, paint stripper sin arts, coating removers, metal aerosols, and aerosol degreasing applications), this use is  no longer allowed for these applications. Refer to this guide for examples of products containing DCM.
3. Please note that the use of DCM in facilities for non-laboratory purposes is prohibited unless the use is specifically exempted by the EPA Final Rule. Please submit a Chemical Waste Pickup Request Form.  Please remove the DCM from the lab’s chemical inventory to reflect its disposal.
4. If your lab is using DCM or plans on future use, you must fill out the DCM Survey Form. by October 31, 2024. This information will then be used to develop a plan that complies with the new EPA regulations and does not adversely affect your work
5. If your lab is interested in substituting another solvent for DCM, please refer to Table 3 and/or contact EHRS at [click-for-email] with any additional questions or concerns.

Please note that other chlorinated solvents such as 1,2-dichloroethane are under EPA review and are likely to be placed under similar restrictions. Therefore, they should not be considered as alternatives. 

Workplace Chemical Protection Program (WCPP)

All researchers unable to eliminate methylene chloride from their processes must develop a WCPP to limit employee exposure. EHRS staff will assist in WCPP implementation and provide resources where possible. The program will include:

• Initial monitoring: All employees or a single individual in an area representing the worst-case scenario will be monitored by EHRS for methylene chloride exposure.

• Establishment of a regulated area: Areas where airborne concentrations of methylene chloride exceed exposure limits will be marked as a designated area with restricted access.

• Exposure control plan: All users must identify and implement exposure controls to reduce inhalation exposure to a level at or below the 8-hour TWA (2 ppm) or STEL (16 ppm). This may include a description of the regulated area, engineering controls, restricted access to regulated areas, and reporting procedure for any changes that may increase employee exposure.

• Respiratory Protection and Personal Protective Equipment (PPE): Respiratory protection (supplied air) will be required in areas when inhalation exposure exceed acceptable limits. Chemical resistant gloves such as polyvinyl alcohol (PVA) or Silver Shield are required to prevent dermal exposure.
• Training: Staff will undergo training prior to working in methylene chloride restricted areas.

• Periodic Monitoring: Restricted areas will be monitored periodically by EHRS staff for inhalation exposure depending on risk or if there are procedural changes.  Exposure levels below the action limit (1 ppm) for the 8-hour TWA and at or below the STEL (16 ppm) will be monitored every 5 years. All other concentrations will require monitoring every 3 or 6 months depending on severity.   

Fact Sheets

• Final Rule for DCM Under TSCA (WCPP)
• More about DCM

Other Resources

• OSHA 1910.1052 Methylene Chloride
• EPA Methylene Chloride; Regulation under Section 6(a) of the Toxic Substances Control Act
• EPA Compliance Guide: Regulation of Methylene Chloride under TSCA
• EPA Risk Evaluation of DCM
• EPA Unreasonable Risk Determination