EPA Regulation Under TSCA
In April 2024, the Environmental Protection Agency (EPA) issued a final rule regulating methylene chloride (dichloromethane or DCM, CAS # 75-09-2) under the Toxic Substances Control Act (TSCA). The EPA has determined this substance poses unreasonable risk to human health primarily due to neurotoxicity from short-term exposure to the chemical and liver effects and cancer from long-term exposure. This new regulation effectively prohibits most industrial and commercial uses of methylene chloride. As a result of this regulation, the vast majority of non-laboratory use of DCM on campus must be discontinued. In fact, many of these products have been discontinued by manufacturers, or their distribution has been banned, as a direct result of these regulations.
The EPA rule has provided an exception to allow laboratory use of DCM to continue, but this use includes new and strict regulatory requirements. This regulation will effectively ban all open use of DCM outside of containment (e.g. fume hood, glove box). EH&S is in the process of developing the framework to meet these regulations. Only EH&S approved procedures will be allowed.
In order for campus to meet these regulations, these are the dates to know:
- May 1, 2025: All labs with DCM must submit their DCM Survey prior to this date.
- July 18, 2025: All units that are not labs and are using or storing DCM products must contact the Office of Chemical Safety for a waste pickup.
- August 1, 2025: Only approved procedures can continue past this date.
EH&S is currently evaluating the campus use of DCM, generating general use SOPs, conducting exposure monitoring, and developing an initial workplace protection plan. More information will be provided as data is gathered and the regulatory deadlines approach, but due to the restrictions it may be prudent for many labs to eliminate the use of DCM altogether.
Contact
Office of Chemical Safety
chemsafety@wisc.edu
Phone: 608-265-5700
Environmental & Occupational Health
eoh@fpm.wisc.edu
608-890-1992
What to Do?
Laboratory Use
Labs that plan to continue to use of methylene chloride must:
- Evaluate options to eliminate or substitute for a safer alternative.
- Review current procedures and identify potential sources of high exposure. Implement controls to minimize exposures wherever possible.
- Complete the DCM Survey to briefly describe your intended operations
After receipt of the survey EHS will review the operations and determine if the procedure falls within the boundaries of tested and approved procedures. If it does, the use will be approved and work can continue with appropriate updates to the laboratory chemical hygiene plan as described below. Uses that fall outside of tested and approved procedures must be reviewed, and air monitoring will be conducted as determined by EH&S. Any work not reviewed and approved by August 1st, 2025, must be suspended until the lab has had an assessment completed by EH&S.
All laboratories should review their chemical storage areas to ensure an accurate inventory of all DCM and DCM-containing (≥0.1%) mixtures. Any unwanted or unneeded inventory of DCM should be submitted for disposal via EHS and removed from inventory.
The vast majority of non-laboratory use of DCM must be discontinued with the implementation of these new regulations, and substitute products should be utilized. Note that retail distribution of many DCM products were previously banned by the EPA, specifically for use as paint and coating removal, but the newest regulation specifically prohibits industrial and commercial use.
All non-laboratory DCM and DCM-containing products (mixtures with ≥0.1% DCM) should be submitted for a waste pickup by July 18, 2025.
DCM can be found in a range of maintenance, cleaning and art items. Please review this list to determine if you have any products with dichloromethane, also known as methylene chloride, in them. You may find these products in:
- Adhesives and bonding agents (consumer and industrial).
- Lithography supplies.
- Paint strippers and paint brush cleaners.
- Textile and upholstery cleaners.
- Varnish removers.
- Adhesives and bonding agents (consumer and industrial).
- Paint strippers and paint brush cleaners.
- Varnish removers.
- Anti-spatter aerosol for welding.
- Automotive care products.
- Carbon remover.
- Cleaners for electric motors, generators, switches, office machinery, tools, PC boards, brakes and carburetors.
- Lubricants and greases.
- Refrigerants.
- Sealants
- Adhesives and bonding agents (consumer and industrial).
- Cleaners for electric motors, generators, switches, office machinery, tools, PC boards, brakes and carburetors.
- Cold pipe insulation and insulation adhesives.
- Lubricants and greases.
- Paint strippers and paint brush cleaners.
- Refrigerants.
- Sealants.
- Textile and upholstery cleaners.
- Varnish removers.
If you have any questions, please contact EH&S.
Controlling DCM Exposures
The most effective way to control a hazard is to remove the hazard, which is why the hierarchy of controls begins with the options of elimination and substitution. If DCM cannot be removed, engineering controls (fume hoods, glove boxes) are more effective that administrative rules (volume limitations, procedural changes). PPE is the last line of defense and the least effective method of control.
Elimination
If you no longer use, or no longer need to use DCM, submit these containers for a surplus chemical pickup. Dispose of all commercial products in your area that contain methylene chloride (paint strippers, brake cleaners, adhesives, lubricants, etc.). Check the product label and the safety data sheet for the presence of methylene chloride (dichloromethane)—contact EH&S if you need assistance.
It is also important to note that it is very likely these regulations will impact the cost and availability of DCM.
Finding a Substitute for Methylene Chloride
Where possible, consider substituting DCM with a safer alternative. Below are some resources to help identify substitutions.
- The Lab Safety Institute Use This Not That: Safer Substitutions for Methylene Chloride (Free Webinar)
- American Chemical Society Solvent Selection Tool
- Green Solvent Selection Tool
- A convenient guide to help select replacement solvents for dichloromethane in chromatography
- Chlorinated solvents: their advantages, disadvantages, and alternatives in organic and medicinal chemistry.
- Greener solvent alternatives
Implementing Controls for DCM
There are things your lab can do now to help control potential exposure to DCM and increase the likelihood that the use of DCM can continue in your lab.
- Perform all possible DCM work in the fume hood.
- Do not store or use DCM squeeze bottles on the bench top.
- Only dispense DCM into secondary containers in the fume hood. If the primary container is too large to put in the fume hood (e.g. 20 L keg), purchase DCM in smaller units (e.g. 4 L bottle) that are easier to handle.
- Move hazardous waste containers into the fume hood when pouring DCM waste.
- Cap samples, flask, round bottoms, etc, when transferring solutions around the lab.
- Make sure solvent and waste flasks on analytical equipment are properly sealed.
- Move rotovaps or other non-vented equipment into the fume hood.
If you have any questions, please contact EH&S.
Understanding the EPA Regulations
New Exposure Limits
OSHA regulates exposure limits for hazardous chemicals in the workplace. While DCM has been specifically regulated by OSHA for some time, those regulations were straightforward for most labs to manage within the framework of our Campus Chemical Hygiene Plan. The new EPA regulation severely reduced the exposure threshold relative to the OSHA standard (See Table 1), and the standard laboratory controls are not necessarily enough to comply with these new regulations. 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). This rule does NOT permit the use of cartridge respirators due to the short service life of cartridges when used for methylene chloride exposure. For more information, see § 751.109(f)(2) and OSHA 1910.134(a).
| Rule | 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 |
Table 1: Comparison of the new EPA rule vs the existing OSHA methylene chloride exposure limits.
Workplace Chemical Protection Program
All researchers unable to eliminate DCM from their processes will need to update their laboratory specific chemical hygiene plan to incorporate a workplace chemical protection program (WCPP) into in order to ensure minimal employee exposure. EH&S staff will assist in the WCPP implementation by incorporating the necessary material into the campus chemical hygiene plan as well as providing templates to complete SOPs within the laboratory specific chemical hygiene plan. The program will include:
- Initial monitoring – Exposure monitoring will be conducted by EH&S for all use of DCM. EHS shall determine when representative samples are appropriate.
- 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. Regulated areas are incredibly burdensome to establish and maintain, both for the users and for EH&S. Approval of DCM work that requires such areas are expected to be incredibly rare.
- 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) is required in areas when inhalation exposure exceed acceptable limits, but EHS will not likely approve these procedures due to the complexity of instituting a lab respiratory protection plan utilizing supplied air respirators. 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 EH&S 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.
Regulatory Dates
These requirements are mandated to be completed according to the following timeline:
- May 5, 2025: Complete initial exposure monitoring. All labs must submit their DCM Survey prior to this date.
- August 1, 2025 or three months after monitoring: Implement controls
- October 30, 2025: Develop and implement an Exposure Control Plan