New EPA Regulations for Methylene Chloride Use

Methylene chloride, also called dichloromethane (DCM), is a widely used solvent in various consumer and commercial applications. It is also commonly found in academic research labs. The Environmental Protection Agency (EPA), under the Toxic Substance Control Act (TSCA), has determined that methylene chloride presents an “unreasonable risk to human health or the environment.” In April 2024, a final rule was issued prohibiting most consumer and commercial uses, with an exemption for laboratory use, provided that a workplace chemical protection program is implemented.

Health Risks

Methylene chloride presents both non-cancer and cancer health risks from acute and chronic inhalation and skin contact. Exposure may increase the risk of cancer, as suggested by some animal studies, and can lead to neurotoxic effects such as headaches and dizziness, as well as heart and liver damage, and skin or eye irritation.

New Exposure Limits

The new EPA regulation severely reduces the exposure threshold relative to the Occupational Safety and Health Administration (OSHA) standard (See Table 1 below). 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).

Table 1: OSHA Vs the New EPA Methylene Chloride Exposure Limits.

Exposure Limits  OSHA  New EPA
8-Hour Time Weighted average (TWA)  25 ppm 2 ppm
15-Minute Short Term Exposure Limit (STEL)  125 ppm  16 ppm
Action Level 12.5 ppm  1 ppm

Under this rule, the EPA allows limited and controlled continued use for research purposes with additional work protections. Environmental Health and Safety (EHS) will help the university community adapt to this new Rule in the following ways:

  • Identify users of methylene chloride.
  • Assist in removing and disposing of methylene chloride through EHSA Pick-Up Requests.
  • Assist with identifying solvent alternatives.
  • Perform initial exposure monitoring to determine exposure levels and notification of additional required work protections.
  • Conduct periodic monitoring to ensure levels remain below allowable concentrations.
  • Provide training on the safe and legal use of methylene chloride.
  • Develop a Methylene Chloride Exposure Control Plan.

Required Actions for Research and Laboratory Groups:

  1. Ensure someone from the lab, the PI or the Secondary Safety Contact, has completed the Methylene Chloride (Dichloromethane, DCM) Usage Survey.
  2. Assess the chemicals and products in your laboratory for methylene chloride. You may need to consult the safety data sheet (SDS) for some products to determine their ingredients.
    1. Please utilize this list of methylene chloride-containing products to evaluate what products may contain methylene chloride.
    2. Check any biological kit components that are utilized in your laboratory as some of these may contain methylene chloride.
    3.  Assess paints, paint stripper, adhesives, lubricants, metal cleaners, etc.
  3. If you currently have methylene chloride in your laboratory and do NOT use it, or you currently have methylene chloride or methylene chloride containing products that are NOT being used for research purposes, submit an EHSA pick-up request and remove it from your chemical inventory.
  4. If you utilize methylene chloride for research purposes:
    1. Ensure that it is listed in your chemical inventory.
    2. Ensure that the use of methylene chloride is documented in your Safety Plan by selecting methylene chloride in the Target Chemical tab. Upon selection, users will be contacted by EHS to assess the use of the chemical.
    3. Write a Standard Operating Procedure (SOP) in EHSA for the use of methylene chloride in your laboratory.
    4. Coordinate with EHS to complete initial exposure monitoring.

Required Actions for non-Research Groups and Work Units:

  1. Ensure someone from the Work Unit has completed the Methylene Chloride (Dichloromethane, DCM) Usage Survey.
  2. Assess the chemicals and products in your workspace for methylene chloride. You may need to consult the safety data sheet (SDS) for some products to determine their ingredients.
    1. Please utilize this list of methylene chloride-containing products to evaluate what products may contain methylene chloride.
    2. Assess paints, paint stripper, adhesives, lubricants, metal cleaners, etc.
  3. If you find chemicals or products in your work space that contain methylene chloride, submit an EHSA pick-up request to have the products removed.
Goal Dates Goal EPA Timeline
October 2024 –November 2024 Survey completed by all methylene chloride users N/A
December 2024 – January 2025
  •  Identify research groups that cannot eliminate the use of DCM
  • Assist research groups in identifying safe alternatives
  • Eliminate locations where DCM is not needed
 N/A
January 2025 –March 2025 Completion of Initial Monitoring for all Laboratories that utilize methylene chloride May 5, 2025 – Completion of Initial Monitoring of Existing Facilities (New Facilities within 30 days of initiating use).
April 2025 –May 2025 Launch of Exposure Control Plan and methylene chloride training and ensure all users are aware and trained August 1, 2025 – Exposure limits and Dermal Protections

October 30, 2025 – Exposure Control Plan/Policy

The use of methylene chloride should follow specific policies and procedures based on your work environment. EHS is currently developing a Methylene Chloride Exposure Control Plan which will include additional information on responsibilities and requirements. If you have questions regarding methylene chloride use, please contact the EHS Research Safety Division at env-health-lab-safety@ncsu.edu.

Alternatives to Methylene Chloride

NOTE: Alternatives suggested in these links have not necessarily been assessed by EHS for safety. Research groups considering alternatives to methylene chloride should fully evaluate the replacement chemical/compounds to ensure they are safe and appropriate for the intended application. Keep in mind that other chlorinated solvents, like 1,2-dichloroethane, are currently under EPA review and may face similar restrictions, so they should not be considered as substitutes.

Other Resources