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Environmental Health and Safety

Methylene chloride

Hazards, risks, and controls to prevent exposure

Methylene chloride, also known as dichloromethane is a volatile, colorless liquid that has a moderately sweet aroma. 

Being highly volatile and heavier than air makes methylene chloride a serious inhalation hazard.  Acute inhalation will cause central nervous system depression, unconciousness, and even death.  Once inside the body, methylene chloride is metabolized to formaldehyde and carbon monoxide so that chronic exposure may produce symptoms similar to carbon monoxide exposure. Symptoms may include headache, nausea, vomiting, confusion, and dizziness.  Skin contact may cause irritation and burns. In addition, methylene chloride is a suspect carcinogen.

The Occupational Safety and Health Administration (OSHA) recently established the Methylene Chloride Standard to prevent occupational exposure to methylene chloride used in the workplace.  To comply with this standard, all users of methylene chloride in USC laboratories must develop and/or complete the following:

  1. EH&S Chemical and Laboratory Safety training
  2. EH&S Hazardous Waste training
  3. Written standard operating procedure (SOP) for the specific use of methylene chloride in your laboratory
  4. In-house lab specific training that includes discussion on methylene chloride SDS and SOP and all controls that need to be implemented to prevent exposure to methylene chloride  

In addition, laboratory personnel are required to follow these specific guidelines when handling methylene chloride:

  • be familiar with the dangers of methylene chloride including its health effects, symptom of exposure and safety requirements by reading the SDS and understanding the content of the written SOP
  • demonstrate competency in following the SOP and the associated scientific methodology
  • use methylene chloride only inside a functioning fume hood or in a closed system designed to prevent the escape of vapors
  • if using outside of a fume hood, contact EH&S (803) 351-9874
  • avoid production of aerosols when handling the liquid
  • wear proper lab attire and laboratory coat
  • use safety glasses with side shield or properly fitted safety goggles 
  • use gloves that are resistant to methylene chloride (e.g., “Silver Shield”, polyvinyl alcohol, Viton, or “Barrier”)
  • remove gloves properly by not touching the contaminated side of the glove then wash hands with soap and water
  • keep away from aluminum metal, oxidizers, strong acids, and amines
  • store only in closed and sealed containers (storage in squirt bottles, beakers, flasks, etc. will allow vapors to escape)
  • clean up spills contained in a fume hood
  • if spilled outside the fume hood - evacuate the area and call EH&S (803) 777-5269, (803) 7275706 for assistance
  • collect, label, store, and dispose of waste methylene chloride according to USC Hazardous waste policy


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