Methylene chloride, also known as dichloromethane (DCM), is a solvent frequently used in various consumer, commercial, and research applications. At NDSU, it is commonly found in academic laboratories. In April 2024, the EPA issued afinal rule under the Toxic Substance Control Act (TSCA), determining that methylene chloride poses an "unreasonable risk to human health." As a result, most consumer and commercial uses of methylene chloride are now prohibited. However, laboratory use is exempt if a Workplace Chemical Protection Program (WCPP) is established and maintained to control exposure.

If your research cannot eliminate methylene chloride, work with the Safety Office to develop a WCPP and implement necessary controls to comply with the new EPA regulations. Ensure your department completes the Methylene Chloride Use Survey and reviews your chemical inventory.

DCM Use Survey

For more information, please contact the NDSUSafety Office at:

ndsu.wastehandlingprogram@ndsu.edu or 701-231-7759.

Methylene chloride poses significant health risks through both inhalation and dermal exposure. These include:

• Cancer Risk: Some animal studies link methylene chloride exposure to an increased cancer risk.
• Neurotoxicity: Short-term exposure may lead to headaches, dizziness, and cognitive effects.
• Heart and Liver Damage: Prolonged exposure can damage vital organs.
• Skin and Eye Irritation: Direct contact can cause irritation or injury.

It is crucial that NDSU researchers understand these risks and work to minimize exposure in accordance with the new regulations.

2024 EPA Exposure Limits

The 2024 EPA regulations have significantly lowered the permissible exposure limits for methylene chloride, surpassing OSHA's previous standards. These changes are critical for ensuring safer work environments at NDSU.

For perspective, the odor threshold of methylene chloride up to 250 ppm—125 times the new 8-hour TWA limit of 2 ppm. This underscores the need for strict adherence to safety protocols.

The NDSU Safety Office is requesting all principal investigators or lab supervisors to:

1. Complete the Methylene Chloride Use Survey: Review your areas for any sources of methylene chloride, including commercial products that contain methylene chloride (e.g., paint strippers, adhesives, metal cleaners).
2. Dispose of Methylene Chloride: Safely dispose of any unused methylene chloride products or consider switching to safer alternatives (see table below).
3. Evaluate Alternatives: As other chlorinated solvents (e.g., 1,2-dichloroethane) are also under EPA review, it is recommended not to switch to these chemicals. Instead, use safer alternatives where possible.

If methylene chloride use is unavoidable in your research, you must establish a WCPP to limit exposure and ensure compliance with the new EPA standards. The Safety Office will assist with WCPP implementation and provide resources.

Each laboratory must have a written WCPP (template) available in the lab and submitted to the NDSU Safety Office for record keeping. 

The WCPP includes the following key components:

1. Initial Monitoring

• The Safety Office will coordinate initial monitoring for all employees or individuals in areas using methylene chloride to assess exposure levels. This will include 8-hour and 15-minute time weighted average measurements.

2. Establish Regulated Areas

• Designate specific areas where methylene chloride is used. These areas must have restricted access and be clearly marked.

3. Exposure Control Plan

• Researchers must implement control measures to reduce exposure below the 8-hour TWA (2 ppm) or the 15-minute STEL (16 ppm). This plan will detail:
  • Regulated areas.
  • Engineering controls (e.g., ventilation). All methylene chloride work must be conducted in an operational fume hood.
  • Restricted access.
  • Reporting procedures for changes that could increase exposure.

4. Respiratory Protection and PPE

• Respiratory Protection: Supplied-air respirators will be required when exposure exceeds acceptable limits.
• Personal Protective Equipment (PPE): Use chemical-resistant gloves such as polyvinyl alcohol (PVA) or Silver Shield to prevent skin contact with methylene chloride.

5. Training

• All personnel must complete training before working in areas where methylene chloride is used. This will cover proper handling, exposure risks, and the use of PPE. 
• Methylene Chloride Safety Training is required annually and is available on Vector Solutions. Vector Solutions Course Name:  Methylene Chloride Safety Training (Policy Tile). 

6. Periodic Monitoring

The Safety Office will conduct periodic air monitoring in regulated areas. If exposure levels are below the action level (1 ppm for 8-hour TWA), monitoring will occur every 5 years. Higher concentrations will require more frequent monitoring (every 3-6 months depending on severity). Costs associated with air monitoring will be the responsibility of the lab or department requesting or requiring the testing.