Frequently Ask Questions

The information below will help answer your questions about methylene chloride [dichloromethane (DCM)] use in the workplace. 

What is the Workplace Chemical Protection Program (WCPP)?

• The Workplace Chemical Protection Program requires facilities using methylene chloride to take appropriate measures to meet new EPA inhalation exposure limits, (including a 2 ppm as an 8-hour time weighted average, and a 16 ppm as a 15-min time weighted average) and develop and implement an exposure control plan.

What are the potential health hazards of DCM?

• Acute non-cancer effects
  • For inhalation, effects are mainly on the central nervous system and can include dizziness and headaches at low exposures. At extremely high exposures such as in a confined space, effects are more serious and include loss of consciousness and respiratory depression.
  • For dermal exposure, effects can include skin irritation and burns.
• Chronic non-cancer effects
  • For chronic exposure by inhalation or dermal exposure, effects include liver dysfunction and increase in blood carboxyhemoglobin.
• Cancer
  • For chronic inhalation exposure, methylene chloride is considered possibly carcinogenic, with human data inconclusive, but animal data showing increases in liver and lung cancer.

What data did EPA find that helped them decide to regulate laboratory use?

• Central tendency data from the EPA shows that exposure from inhalation could cause acute effects, as well as chronic non-cancer effects.
• High-end data from the EPA shows that exposure from inhalation could cause acute effects, as well as chronic cancer and non-cancer effects.
• The central and high-end exposure data show that dermal exposure (without proper PPE) could cause acute and chronic non-cancer effects.
• EPA Risk Evaluation for Methylene Chloride, p 320, 329  

What lab activities are most likely to cause overexposure to DCM if not controlled by PPE or ventilation?

• We are currently collecting real-time and lab analyzed sampling data to get a better understanding of exposure  levels present in laboratories where DCM is used. 
• Previous sampling data compiled by the EPA showed 18% of samples were over the new, lowered EPA limits for either 15-minute or full-day exposure by inhalation. These are activities you should prioritize performing in a hood or with other local exhaust ventilation. These activities included:
  • Collecting waste and dumping into other containers
  • Washing separatory funnels in the sink near continuous extraction
  • Performing Toxic Characteristic Leaching Procedure (TCLP) procedures
  • Sample extraction and analysis
  • Extraction of contaminants from water samples
  • Column Cleaning
• For more information on EPA exposure estimates for common lab uses of DCM  please see the EPA Risk Evaluation for Methylene Chloride, p 172-174  

My lab is being sampled for DCM exposure, what should I expect?

• If 8 h inhalation exposure sampling is being conducted, you may be asked to wear a passive absorption badge (see the Badge Sampling Procedure video). Open the badge at the beginning of your work activity, attach it to your shoulder, and record the start time. Perform your normal lab activities as if you were not being monitored. When you are done working in the lab for the day, close the badge, put the badge in the sealable bag provided, and record the time. Contact HSRM ([email protected]) to  collect the badge(s) for analysis.   
• Task specific inhalation exposure may also be conducted using a passive absorption badge (see use instructions above) or a portable GasMet DX5050 multi gas FTIR analyser. An open ended plastic hose tethered to the instrument will be attached to your shoulder. A technician will monitor your DCM exposure in real time while you perform the task. Advice for how to minimize exposure during the task may be given by the technician.   
• If dermal exposure sampling is being conducted, you may be asked to wear a band-aid like device on a few of your fingers and palm to determine whether any solvent is penetrating through your gloves during the sampling time. 
  • These devices will generally display results colorimetrically to let you know if your gloves are adequate or not. 

What can I do now to minimize my exposure to DCM?

• Prioritize working with DCM 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 rotovapes or other non-vented equipment into the fume hood whenever feasible. 

Will I have to change lab operations?

• Most labs that use DCM will likely have to make some adjustments to current practices, procedures, and laboratory controls.
  • Areas found to have exposures above the EPA ECEL (2 ppm as an 8-h TWA) and EPA STEL (16 ppm as a 15-min TWA) exposure limits will need to implement additional ventilation controls or provide supplied air respirators to exposed employees. Traditional elastomeric respirators with chemical cartridges are not considered appropriate respiratory protection under the EPA TASCA ruling. 
    • Labs that are found to have exposure limits above the EPA ECEL and STEL will need to have exposure monitoring performed every 3 months. 
    • Labs that are found to have DCM exposures above 1 ppm but below the EPA ECEL and STEL will need to have exposure monitoring performed every 6 months. 
    • Labs that are found to have DCM exposures below 1 ppm and below the EPA ECEL and STEL will need to have exposure monitoring performed every 5 years or whenever changes are made to laboratory procedures or ventilation controls. 
  • You may have to make changes to your current glove use.
    • The EPA recommends poly vinyl alcohol or Silver Shield gloves. However, dexterity may be diminished with either of these products. Wearing standard nitrile gloves over your Silver Shield ones may offer some improvement.
    • We are currently looking into alternative glove options and measuring breakthrough exposures for task-based work. Additional guidance will be provided in the coming months. 

I am worried that I have been overexposed to DCM currently or in past practices at UMN, who can I talk to?

1. Report the work-related exposure. 
   Complete an electronic first report of injury. This initiates the worker’s compensation process and ensures your consultation will be covered by the University of Minnesota. 
   
   You will receive an email confirmation with a 9-digit claim number, which must be referenced to schedule the consultation. 
2. Schedule a consultation. 
   Visit the Clinical Services website to schedule a consultation with an occupational health provider in your area. 
   
   Inform the scheduler that you are a University of Minnesota employee that has had a potential overexposure to DCM and would like to make a consultation with the provider. 

If you have questions about this process or would like to consult with someone about a specific DCM exposure concern please email University Occupational Health ([email protected]).