EPA Methylene Chloride Regulation

Last Revised: October 23, 2024

Issue Date 8/6/2024; Rev. Dates 8/26/2024, 10/7/2024, 10/23/2024

The EPA issued a new regulation, Methylene Chloride; Regulation Under the Toxic Substances Control Act (TSCA), in May 2024.  Under this new regulation, EHRS is required to conduct exposure monitoring for all uses of methylene chloride on campus. 

EHRS is reaching out to labs who list methylene chloride (dichloromethane) in their chemical inventory and asking them to complete this Methylene Chloride Usage Form to help us identify areas where monitoring will be needed.  To help EHRS manage this new regulation, it is critical to keep your lab’s chemical inventory up to date. 

Below are answers to the most common questions about this new regulation, including changes to methylene chloride waste collection. If you have additional questions or concerns, please reach out to EHRS at 215-898-4453 or ehrs@ehrs.upenn.edu.

Why is the EPA regulating methylene chloride?

The EPA determined that methylene chloride presents an unreasonable risk to human health. Methylene chloride is classified as a potential human carcinogen and is toxic to the central nervous system and the liver. Exposure to methylene chloride can occur from inhalation and skin absorption.  At least 85 deaths have resulted from exposures to high levels of methylene chloride, primarily during paint-stripping and bathtub refinishing activities in poorly ventilated areas.

Does this regulation apply to academic research labs?

This regulation applies to all research, government, academic, industrial, and commercial laboratories. Additionally, this regulation applies to all potentially exposed laboratory personnel, including students, interns, and visitors.

What is required to continue using methylene chloride?

The EPA requires employers to implement a Workplace Chemical Protection Program (WCPP) to protect laboratory personnel from exposure to methylene chloride. Under the WCPP, we are required to:

  • Meet the exposure limits for methylene chloride established by the EPA. The EPA exposure limits are lower than the exposure limits established by OSHA.
  • Conduct exposure monitoring for all potential methylene chloride exposures.
  • Establish a regulated area when airborne concentrations of methylene chloride exceed, or there is a reasonable possibility they may exceed the exposure limits.
  • Develop and implement a methylene chloride exposure control plan that identifies the controls that will be used to reduce exposures to below the exposure limits.

Exposure Limit

Description

EPA

OSHA

8-hour time-weighted average (TWA)

Average concentration over 8-hour period

2 ppm

25 ppm

15-minute short term exposure limit (STEL)

Average concentration over 15-minute period

16 ppm

125 ppm

 

How can I reduce my exposure to methylene chloride?

As mentioned previously, exposure to methylene chloride can occur from inhalation and skin absorption. It is important that control measures are in place to prevent both inhalation and skin contact. Methods for controlling methylene chloride exposure are listed below in order of most effective to least effective:

Elimination or Substitution

If possible, eliminate the use of methylene chloride or replace methylene chloride with a safer alternative. If you are able to eliminate the use of methylene chloride in your lab, submit a waste pickup request via the Chemical Waste Pickup Form and remove methylene chloride from your chemical inventory.

Engineering Controls

When elimination or substitution is not feasible, engineering controls are the next most effective control method. Chemical fume hoods are the most common engineering control found in laboratories. Work with methylene chloride in a fume hood whenever possible. If a fume hood is not available or is not able to be used for a specific application, contact EHRS to assist with identifying appropriate alternative controls.

Administrative Controls

Implement work practices that reduce the quantity of methylene chloride used, the duration of exposure, and/or the frequency of use if possible. The required establishment of a regulated area is an example of an administrative control.

Personal Protective Equipment (PPE)

Unfortunately, PPE for methylene chloride is not straightforward. Many common glove materials do not provide protection from methylene chloride, including nitrile, latex, neoprene, and butyl rubber. Methylene chloride permeates disposable nitrile gloves within one minute. If you have the potential for hand contact with methylene chloride, one solution that will provide good protection and dexterity is to double glove with Silver Shield® gloves as the inner gloves and disposable nitrile gloves as the outer gloves. Contact EHRS for additional glove selection assistance.

Respiratory protection is not an option for controlling inhalation exposures to methylene chloride in the lab. Filter cartridge respirators cannot be used because methylene chloride can pass through the cartridge leaving respirator wearers unprotected.

How do I find substitutes for methylene chloride?

Substitutes for methylene chloride may be available depending on your application. The American Chemical Society (ACS) has several tools available to assist with identifying substitutes on their Tools for Innovation in Chemistry page. Please be aware that some substitutes may introduce a different hazard, such as flammability. EHRS is available to consult with you as you identify substitutes to ensure any new hazards are identified and properly controlled.

What is exposure monitoring and how will this be done?

Exposure monitoring measures a person's exposure to airborne chemicals during use. There are several different methods for conducting exposure monitoring, and the method selected will be based on the specific use scenario.

I only use methylene chloride in a fume hood. Will exposure monitoring be done?

Yes, the EPA has stated that while a properly working fume hood should be sufficient to control methylene chloride exposures, exposure monitoring is needed to demonstrate the protection provided.

What information will EHRS need to conduct required exposure monitoring?

EHRS is reaching out to labs who list methylene chloride (dichloromethane) in their chemical inventory and asking them to complete this Methylene Chloride Usage Form to help us identify areas where monitoring will be needed. The information below will help us to prioritize and schedule exposure monitoring:

  • How methylene chloride is used in your lab.
  • Quantity used.
  • Frequency of use.
  • Number of lab personnel using methylene chloride.

 

To help EHRS manage this new regulation, it is critical to keep your lab’s chemical inventory up to date.

How can I check if my lab has methylene chloride in its ChemTracker inventory?

The best way to search for methylene chloride in your inventory is by its CAS Registry Number, not by chemical name. Go to your lab’s ChemTracker tab in BioRAFT, and in the “CAS Number” field at the top, enter the CAS number for methylene chloride, 75-09-2. This will bring up results for both methylene chloride and its other name, dichloromethane. 

Is there a change to how methylene chloride waste is collected?

Yes. To minimize methylene chloride exposure by EHRS staff during waste consolidation activities, EHRS is requesting that methylene chloride waste (even small amounts) be segregated from aqueous and non-halogenated waste streams. Methylene chloride waste can still be combined with other halogenated waste streams. Please make sure that methylene chloride is clearly listed on the waste tag. To help labs segregate methylene chloride waste, containers of various sizes can be requested from EHRS via the Chemical Waste Pickup Form.

What else can my lab do?

Three things your lab can do to assist us with complying with this new regulation are:

  • Ensure your chemical inventory is up to date. Contact the EHRS chemical inventory team at cheminv@ehrs.upenn.edu with any questions about the ChemTracker system.
  • Ensure that waste tags are properly filled out, clearly identifying when methylene chloride is a constituent of the waste container. In addition to methylene chloride exposures in labs, we are focused on reducing exposures to the EHRS team who collects and consolidates chemical waste.
  • Identify old and unused containers of methylene chloride in your lab and submit a waste pickup request via the Chemical Waste Pickup Form.