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Methylene Chloride

General Description

  • Synonyms: Methylene dichloride; Dichloromethane
  • OSHA IMIS Code Number: 1730
  • Chemical Abstracts Service (CAS) Registry Number: 75-09-2
  • NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: PA8050000
  • Department of Transportation Regulation Number (49 CFR 172.101) and Emergency Response Guidebook: 1593 160
  • NIOSH Pocket Guide to Chemical Hazards, Methylene Chloride: Chemical description, physical properties, potentially hazardous incompatibilities, and more
  • U.S. Environmental Protection Agency (EPA) Hazard Summary, Methylene Chloride: Uses, sources and potential exposure, acute and chronic health hazard information, and more

Exposure Limits and Health Effects

Exposure Limit Limit Values HE Codes Health Factors and Target Organs
OSHA Permissible Exposure Limit (PEL) - General Industry
See 29 CFR 1910.1052
  • 25 ppm
  • TWA
  •  
  • 125 ppm
  • STEL
  •  
  • 12.5 ppm
  • Action Level
HE1 Cancer
HE3 Cardiac and liver toxicity 
HE7 Lightheadedness, staggering, unconsciousness, decreased eye/hand coordination, numbness of the extremities
HE8 Central nervous system effects/narcosis
HE14 Eyes, nose, throat, skin irritation
HE17 Chemical anoxia (metabolic conversion to CO)
OSHA PEL - Construction Industry
See 29 CFR 1926.1152
  • 25 ppm
  • TWA
  •  
  • 125 ppm
  • STEL
  •  
  • 12.5 ppm
  • Action Level
HE1 Cancer
HE3 Cardiac and liver toxicity 
HE7 Lightheadedness, staggering, unconsciousness, decreased eye/hand coordination, numbness of the extremities
HE8 Central nervous system effects/narcosis
HE14 Eyes, nose, throat, skin irritation
HE17 Chemical anoxia (metabolic conversion to CO)
OSHA PEL - Shipyard Employment
See 29 CFR 1915.1052
  • 25 ppm
  • TWA
  •  
  • 125 ppm
  • STEL
  •  
  • 12.5 ppm
  • Action Level
HE1 Cancer
HE3 Cardiac and liver toxicity 
HE7 Lightheadedness, staggering, unconsciousness, decreased eye/hand coordination, numbness of the extremities
HE8 Central nervous system effects/narcosis
HE14 Eyes, nose, throat, skin irritation
HE17 Chemical anoxia (metabolic conversion to CO)
National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL)
See Appendix A
  • Lowest feasible concentration
  • Ca
HE1 Cancer
American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) (2001)
(Listed under dichloromethane)
  • 50 ppm
  • (174 mg/m3)
  • TWA
  •  
  • A3, BEI
HE4 Cardiovascular changes
HE7 Neurological effects (headache, dizziness, loss of balance, memory difficulties, numbness in hands or feet)
HE8 Central nervous system effects (narcosis)
HE17 Asphyxiant, anoxiant
CAL/OSHA PELs
See Section 5202
  • 25 ppm
  • (87 mg/m3)
  • TWA
  •  
  • 125 ppm
  • (435 mg/m3) STEL
   

National Toxicology Program (NTP) carcinogenic classification: Reasonably anticipated to be a human carcinogen (PDF)

International Agency for Research on Cancer (IARC) carcinogenic classification: Group 2B (PDF) (possibly carcinogenic to humans)

EPA carcinogenic classification: Likely to be carcinogenic to humans

EPA Inhalation Reference Concentration (RfC): 0.6 mg/m3

Agency for Toxic Substances and Disease Registry (ATSDR) Inhalation Minimal Risk Levels (MRLs): 0.6 ppm (acute); 0.3 ppm (intermediate); 0.3 ppm (chronic)

NIOSH Immediately Dangerous to Life or Health (IDLH) concentration: 2,300 ppm

Notes on Other Potential Health Effects and Hazards

  1. Combustible under specific conditions. Gives off irritating or toxic fumes (or gases) in a fire (NIOSH/IPCS 1994).
  2. Case studies of methylene chloride poisoning during paint-stripping operations have demonstrated that inhalation exposure can be fatal to humans (ATSDR 2000).
  3. Thirteen deaths of bathtub refinisher fatalities associated with methylene chloride stripping agents have occurred during 2000-2011. Each death occurred in a residential bathroom with inadequate ventilation (CDC 2012).
  4. NTP concluded that methylene chloride administered by inhalation caused liver, lung, and breast tumors, which was sufficient evidence to classify methylene chloride as reasonably anticipated to cause cancer.
  5. The EPA reference concentration was established based on liver effects in a laboratory inhalation study in rats.

Date Last Revised: 12/11/2012

Literature Basis:

Monitoring Methods used by OSHA

Laboratory Sampling/Analytical Method:
  • Carbosieve S-III Tube (130/65 mg sections, 60/80 mesh)
  • analytical solvent: (99:1) Carbon Disulfide/Dimethylformamide
  • maximum volume: 3 Liters
  • maximum flow rate: 0.05 L/min (TWA)
  • minimum time: 5 Minutes
  • maximum flow rate: 0.05 L/min (Ceiling or STEL)
  • minimum time: 5 Minutes
  • maximum flow rate: 0.05 L/min (Peak)
  • current analytical method: Gas Chromatography; GC/FID
  • method reference: OSHA Analytical Methods (OSHA 80)
  • method classification: Fully Validated
  • Charcoal Tube (350/350/350 mg sections, 20/40 mesh)
  • analytical solvent: Carbon Disulfide
  • alternative solvent: (99:1) Carbon Disulfide/Dimethylformamide
  • maximum volume: 10 Liters
  • maximum flow rate: 0.05 L/min (TWA)
  • minimum time: 5 Minutes  
  • maximum flow rate: 0.05 L/min (Ceiling or STEL)
  • minimum time: 5 Minutes
  • maximum flow rate: 0.05 L/min (Peak)
  • current analytical method: Gas Chromatography; GC/FID
  • method reference: OSHA Analytical Methods (OSHA 59)
  • method classification: Fully Validated

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