1. OSHA Occupational Chemical Database
  2. METHYL CHLORIDE
Label abbreviations descriptions

METHYL CHLORIDE†

Chemical Identification
Chemical Identification
CAS # 74-87-3
Formula

CH₃Cl
Synonyms

chloromethane; monochloromethane
Physical Properties
Physical Properties
Physical description Colorless gas with a faint, sweet odor which is not noticeable at dangerous concentrations.
Boiling point -12°F Molecular weight 50.5
Freezing point/melting point -144°F Vapor pressure 5.0 atm
Flash point -49.0°F Vapor density 1.78
Specific gravity 0.997 at -11.2°F Ionization potential 11.28 eV
Lower explosive limit (LEL) 8.1% Upper explosive limit (UEL) 17.4%
NFPA health rating 2 NFPA fire rating 4
NFPA reactivity rating 0 NFPA special instruction
Vapor hazard ratio (VHR)
Historical exceedance percentage
Target organs
Monitoring Methods Used by OSHA
Monitoring Methods Used by OSHA
Analyte code (IMIS no.) 1710
Sampling group
Sampler/Sampling media 2 CSC tubes in series (first tube 400/200 mg, second tube 100/50 mg) [SKC 226-09 & SKC 226-01]
Sampling time*
 

 
Sampling volume (TWA)*
 

0.4-3 L
Sampling flow rate (TWA)*
 

0.01-0.1 L/min
Sampling volume (STEL/Peak/C)*
 

 
Sampling flow rate (STEL/Peak/C)*
 

 
Analytical method instruments GC-FID
Method reference NIOSH 1001 (fully validated)
Notes
 
 

 
Special requirements
 
 

 

* All sampling instructions above are recommended guidelines for OSHA Compliance Safety and Health Officers (CSHOs), please see the corresponding OSHA method reference for complete details.

Wipe Method
Wipe Method
Sampler/Sampling media
 

 
Bulk Method
Bulk Method
 

 
On-Site Screening Techniques
On-Site Screening Techniques
Device Detector tube Detector tube
Model/Type Gastec 51 Gastec 51L
Sampling information
(see manufacturer instructions) 		1 stroke, approx 10-480 ppm 1 or 2 strokes, approx 1-86 ppm
Exposure Limits
Exposure Limits
OSHA PEL
8-hour TWA
(ST) STEL
(C) Ceiling
Peak
NIOSH REL
Up to 10-hour TWA
(ST) STEL
(C) Ceiling
ACGIH TLV©
8-hour TWA
(ST) STEL
(C) Ceiling
CAL/OSHA PEL
8-hour TWA
(ST) STEL
(C) Ceiling
Peak
PEL-TWA
 

100 ppm (210 mg/m³)

 REL-TWA
 

 

 TLV-TWA
 
 

50 ppm [1992]

 PEL-TWA
 
 

50 ppm (105 mg/m³)
PEL-STEL
 

 

 REL-STEL
 
 

 

 TLV-STEL
 
 

100 ppm [1992]

 PEL-STEL
 
 

100 ppm (210 mg/m³)
PEL-C
 

200 ppm; 300 ppm (Peak - 5 min in any 3 hrs)

 REL-C
 
 

 

 TLV-C
 
 

 

 PEL-C
 
 

300 ppm
Skin notation
 

N

 Skin notation
 
 

N

 Skin notation
 
 

Y

 Skin notation
 
 

N
Notes:
 

Ceiling value applies only to OSHA General Industry standard. TWA applies to OSHA's General Industry and Maritime standards. See 29 CFR 1910.1000 Table Z-2 and 29 CFR 1915.1000 Table Z-Shipyards.

 Notes:
 
 

CARCINOGEN (Ca): REDUCE EXPOSURE TO LOWEST FEASIBLE CONCENTRATION (LOQ 1.6 ppm). See Appendix A, NIOSH Potential Occupational Carcinogens.

 Notes:
 
 

 

 Notes:
 
 

 
Health factors:  See NIH-NLM PubChem. IDLH
 
 

2000 ppm
Carcinogenic classifications: IARC-3, NIOSH-Ca, TLV-A4, EPA-D; CBD Notes:
 
 

Ca
AIHA emergency response planning guidelines - ERPG-1/ERPG-2/ERPG-3:
 
 

150 ppm/1000 ppm/3000 ppm
Additional Resources and Literature References
Additional Resources and Literature References

NOAA: CAMEO Chemicals - Methyl chloride

NIOSH: Pocket Guide to Chemical Hazards - Methyl chloride

Literature References

 
 
  • ACGIH: Documentation of the Threshold Limit Values (TLVs) and Biological Exposure Indices (BEIs) - Methyl chloride. See annual publication for most recent information.
  • EPA Air Toxics Website: Methyl Chloride (Chloromethane). U.S. Environmental Protection Agency Technology Transfer Network.
  • Nelson, H.H., et al., Ethnic differences in the prevalence of the homozygous deleted genotype of glutathione S-transferase theta. Carcinogenesis 16(5): 143-1245, 1995.
  • No authors: Methyl chloride. IARC Monogr. Eval. Carcinog. Risks Hum. 71(Pt. 2): 737-747, 1999.
  • Pohanish, R.P. (editor): Methyl Chloride. In, Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 2. Norwich, NY: Noyes Publications, William Andrew Publishing, 2002, pp. 1537-1540.

Last Updated Date : 01/29/2021