Methylene Chloride Use

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.

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.

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 initial and periodic 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 and mark those areas accordingly.
Develop and implement a methylene chloride exposure control plan that identifies the controls used to reduce exposures to below the exposure limits.
Increase record keeping regarding methylene chloride.
Provide appropriate respiratory selection and other PPE for individuals that may enter the regulated areas.
Conduct training for all individuals that will enter the areas where methylene chloride is used.

Note: In advance of the 2019 EPA ruling, many retailers phased out methylene chloride-containing products. These include Walmart, Lowe’s, Home Depot, Sherwin Williams, and Ace Hardware all by late 2018 or early 2019.

• Varnish remover
• Masonry cleaner
• Graffiti remover
• Paint stripper
• Surface preparation cleaner for painting/gluing
• Adhesive, tape, or tacky remover
• Degreaser / Parts stripper (commonly for metal parts)
• Epoxy dissolver
• Soldering rosin flux remover
• Paint brush cleaner (note this does not include simple mineral spirits nor pure paint thinner, but does include brush deep cleaning solvents or brush restoring cleaners for dried paint)
• Foam dissolver
• Caulk / sealant remover
• Laminate stripper
• Tile remover
• Bathtub refinisher
• Carburetor cleaner
• Choke and valve cleaner
• Brake cleaner (automotive)
• Gasket remover
• Gun / firearm cleaner
• Spray equipment cleaner
• 3-D printer nozzle cleaner
• Contact cement – particularly older spray contact cement (manufacturers or brand names in particular include Hybond, Tensorgrip, Formica, Weld-on; possibly older 3M products)
  Note that Wilson Art Company makes a non-flammable alternative contact cement with no DCM in it as of 2024.
• Wallpaper / carpet glue remover
• Mold-release agents (McLube is one possible name brand)
• Various name brands of all the above products, whose products presently or in the past have contained DCM (especially in strippers / cleaners) include Sterling, Watco, Jasco, Klean-strip, Savogran, Miller-Stephenson, and Zinsser.

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:

1. 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 using CampusOptics.
2. 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 ESD to assist with identifying appropriate alternative controls.
3. 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.
4. 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 ESD for additional glove selection assistance.
   Using air-purifying respirators (APRs) as 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. Breakthrough of APR cartridges offers no indication before the odor threshold, by which overexposure will have occurred.

Substitutes for methylene chloride may be available depending on your application. The American Chemical Society (ACS) has several tools available for identifying substitutes.
Please be aware that some substitutes may introduce different hazards, such as flammability. The Office of Research Safety is available to consult with you to help identify substitutes and to ensure any new hazards are identified and properly controlled.

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.
If I only use methylene chloride in a fume hood, will exposure monitoring still be required?
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.

Yes. Methylene chloride waste will continue to be disposed of adhering to the existing rules for hazardous chemical waste disposal. The primary difference due to this and other upcoming EPA regulations is that users should not fill or pour chlorinated organic waste in the open laboratory, but rather only under ventilation (such as in a fume hood). Halogenated / chlorinated waste containers must be kept capped at all times when stored outside of ventilated space. These apply unless and until exposure monitoring determines whether overexposure may occur with these activities.

To assist us with complying with these new regulations, please ensure your chemical inventory is up to date in CampusOptics. You can also identify old and unused containers of methylene chloride in your lab and dispose of them through CampusOptics.