The U.S. Environmental Protection Agency (EPA) has issued a Final Rule regulating the use of methylene chloride CAS # 75-09-2 (dichloromethane, DCM) under the Toxic Substances Control Act (TSCA). Methylene chloride has multiple uses in a laboratory setting, including purifying, extracting, and as a solvent for many chemical processes. The EPA has determined that methylene chloride represents an "unreasonable risk of injury to health" and the rule, which went into effect in July 2024, bans or restricts almost all uses of the chemical. The rule prohibits consumer use and significantly limits commercial use. The EPA defines work in a laboratory as commercial use, and therefore, university laboratories are subject to the requirements of the regulation. In addition, Not-for-profit entities and colleges/universities are considered commercial users and are subject to the methylene chloride rule. 

Under the new regulation, consumer use of methylene chloride will be phased out within a year, preventing most industrial and commercial uses. While the laboratory use of methylene chloride is not banned, the EPA has issued strict requirements, including stringent exposure limits, monitoring requirements, training, and notification obligations, among other conditions, for any continued use. 

Every department and principal investigator (PI) must check their chemical inventory for anything containing methylene chloride. This includes mixtures where methylene chloride is present >0.1%. 

If your lab stores or uses products containing methylene chloride, the easiest solution would be to either eliminate or substitute it. 

• Elimination: Elimination removes the hazard at the source. This could include changing the work process to stop using methylene chloride or switching to a new process that does not require its use. It is the preferred solution to protect workers because no exposure can occur.
   
• Substitution: Substitution is the process of using a safer alternative to the source of the hazard. If you actively use the chemical or products containing .0.1% methylene chloride, consider alternatives and if they will work as a substitute. 

If you cannot eliminate or substitute methylene chloride in your research, you must develop a Workplace Chemical Protection Program (WCPP) and have exposure monitoring conducted to continue use. The new regulation requires initial exposure monitoring to be completed by May 5, 2025. Rutgers Environmental Health and Safety (REHS) will provide assistance and guidance throughout this process. 

All researchers, in their commitment to the safety and well-being of the occupants of their laboratory, must develop a WCPP if they are unable to eliminate or substitute methylene chloride from their processes. The EPA-designed WCPP requirements, similar to those in the OSHA methylene chloride standard, are crucial for maintaining a safe working environment. REHS can assist in WCPP implementation and provide resources where possible. A WCPP must include the following: 

• Initial and Periodic Monitoring: Workplace air concentrations of methylene chloride must be determined through personal breathing zone samples. These samples are used to determine what actions are necessary to mitigate exposure, such as using engineering controls or personal protective equipment (PPE). Periodic monitoring is then required on a routine basis, as often as every three months to once every five years, depending on the initial monitoring results. 
   
• Regulated Areas: Areas where airborne concentrations of methylene chloride exceed exposure limits must be identified and marked as designated areas with restricted access. 
   
• Personal Protective Equipment: Chemically resistant gloves are required where dermal exposure is possible. The regulation does not allow the use of air-purifying respirators such as half-face and full-face cartridge respirators. Only supplied air respirators (SAR) are permitted by EPA.  Training: Individuals working in methylene chloride restricted areas must complete training 
   
• Training: Individuals working in methylene chloride restricted areas must complete training before initial job assignments. 
   
• Exposure Control Plan: An exposure control plan is required for all users of methylene chloride. The plan 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). The exposure control plan includes, but is not limited to, identification of exposure controls, how the hierarchy of controls is applied to reduce inhalation exposures, a description of exposure control implementation, a description of the regulated area(s) and authorized entry, a description of measures to ensure adequate controls, and procedures for responding to any potential changes. Documentation of the efforts identifying why certain non-feasible, ineffective, or otherwise not implemented is also required for the exposure controls not selected. 
   
• Recordkeeping and Notification: Recordkeeping of training, sampling records, and control plans must be maintained at all times. Notification of potentially exposed persons of the results of workplace exposure monitoring activities and exposure incidents is also required. 

The new EPA regulation also severely reduced the exposure threshold relative to the OSHA standard. Below is a comparison of the OSHA methylene chloride exposure limits to the new EPA rule. 

The lower exposure limits will require that methylene chloride use is limited to fume hoods or incorporates another engineering control to protect the individual working with it. Use outside of a hood will likely require respiratory protection, which under the rule requires the use of Supplied Air Respirator (SAR) or Self Contained Breathing Apparatus (SCBA) respirators only. As stated previously, this rule does not permit the use of air-purifying respirators (APRs) due to the short service life of chemical cartridges when used for methylene chloride exposure. 

While laboratory use of methylene chloride is not banned, compliance with the new regulation is required for any continued use. To meet these requirements, REHS must identify each location where methylene chloride is currently used and plan to continue use after the May 5, 2025 deadline. REHS’s goal is to work with our researchers to meet compliance while doing our best to minimize disruptions to research. 

As a first step in that process, REHS is seeking information on the use of methylene chloride across campus. If you have been identified as a lab that uses or stores methylene chloride, you will receive an email with a survey and instructions. These surveys must be completed and submitted to assist with these new regulatory requirements. Every department and principal investigator must participate in this program inventory. 

Please review your areas for commercial products containing methylene chloride (paint stripers, adhesives, metal cleaners, lubricants, etc.) and dispose of them properly. Research laboratories that have methylene chloride that they wish to dispose of can submit a Request for Hazardous Waste Disposal. 

Please help us spread the word and look for further communication from REHS in the coming weeks and months as we work to minimize the disruptions this new EPA rule may present while always prioritizing the health and safety of our researchers and community. Additional information regarding the new regulation can be found below. 

• Fact Sheet: 2024 Final Risk Management Rule for Methylene Chloride under TSCA 
• A Guide to Complying with the 2024 Methylene Chloride Regulation under TSCA 
• Alternative Solvents to Methylene Chloride