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Safety and Health Topics: |
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| Methyl Chloride |
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General Description
Synonyms: Chloromethane; Monochloromethane
OSHA IMIS Code Number: 1710
Chemical Abstracts Service (CAS) Registry Number: 74-87-3
NIOSH, Registry of Toxic Effects (RTECS) Identification Number: PA6300000
Department of Transportation Regulation Number (49 CFR 172.101) and Guide: 1063 115
NIOSH Pocket Guide to Chemical Hazards, Methyl Chloride: chemical description, physical properties, potentially hazardous incompatibilities, and more
Exposure Limits
OSHA Permissible Exposure Limit (PEL) for General Industry: 29 CFR 1910.1000 Z-2 Table -- 100 ppm TWA; 200 ppm Ceiling for 5 mins. in any 3 hours; 300 ppm Peak
OSHA Permissible Exposure Limit (PEL) for Maritime: 29 CFR 1915.1000 Table Z-Shipyards -- 100 ppm, 210 mg/m3 TWA
American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV): 50 ppm, 103 mg/m3 TWA; 100 ppm, 207 mg/m3 STEL; Skin; Appendix A4 - Not Classifiable as a Human Carcinogen
National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL): Appendix A - NIOSH Potential Occupational Carcinogens
Health Factors
International Agency for Research on Cancer (IARC) carcinogenic classification: Group 3, not classifiable as to its carcinogenicity to humans
NIOSH Immediately Dangerous To Life or Health Concentration (IDLH): 2,000 ppm
Potential symptoms: Dizziness; loss of appetite, nausea, vomiting; blurred or double vision, drooping eyelids, eye twitch; tremors of hands and lips, staggering, slurred speech, "drunken" behavior; headache, memory loss, confusion, hallucinations; convulsions; coma; burning sensation in mouth and throat, mustard-like taste, difficulty swallowing; cold clammy skin, rapid breathing, pulmonary edema; liver, kidney damage; frostbite, corneal burns (from liquid); [potential occupational carcinogen]
Health Effects: Acute CNS effects (HE4); Chronic CNS effects (HE7); Cumulative liver and kidney damage (HE3)
Affected organs: CNS, liver, kidneys, skin, reproductive system
Notes: 1) Studies in rodents indicate that inhalation of methyl chloride can cause fetal growth retardation, impaired fertility in male rats and mouse fetal heart malformations. 2) Toxicity may involve metabolism, in part, to formaldehyde by cytochrome P450 2E1, a liver enzyme inducible by chronic ethanol consumption, and to conjugates of glutathione in red blood cells by glutathione S-transferase theta, an enzyme missing in 10% to 64% of certain ethnic populations.
Date Last Revised: 01/08/2004
Literature Basis:
- NIOSH Pocket Guide to Chemical Hazards: Methyl chloride.
- International Chemical Safety Cards (WHO/IPCS/ILO): Methyl chloride.
- 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.
Monitoring Methods used by OSHA
Laboratory Sampling/Analytical Method:
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sampling media: Two charcoal tubes in series (First tube 400/200 mg sections, second tube 100/50 mg sections, both 20/40 mesh)
analytical solvent: Methylene Chloride
maximum volume: 3.0 Liters maximum flow rate: 0.1 L/min (TWA)
maximum volume: 1.5 Liters maximum flow rate: 0.1 L/min (STEL)
minimum time: 5 Minutes maximum flow rate: 0.1 L/min (Ceiling)
minimum time: 5 Minutes maximum flow rate: 0.1 L/min (Peak)
current analytical method: Gas Chromatography; GC/FID
method reference: NIOSH Manual of Analytical Methods (NIOSH 1001)
method classification: Fully Validated
On-Site Sampling Techniques/Methods:
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device: Pyrotec Tube
manufacturer: Gastec
model/type: 51
sampling information: 1 stroke
upper measurement limit: 480 ppm
detection limit: approximately 10 ppm
overall uncertainty: unknown
method reference: on-site air secondary (manufacturer)
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device: Pyrotec Tube
manufacturer: Gastec
model/type: 51L
sampling information: 1 or 2 strokes
upper measurement limit: 86 ppm
detection limit: approximately 1 ppm
overall uncertainty: unknown
method reference: on-site air secondary (manufacturer)
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| Revised: 16 June 2004 |
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