Skip directly to local search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home
May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)

Methyl chloride

CAS number: 74–87–3

NIOSH REL: None established; NIOSH considers methyl chloride to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990].

Current OSHA PEL: 100 ppm TWA, 200 ppm CEILING,

300 ppm 5-minute MAXIMUM PEAK IN ANY 3 HOURS

1989 OSHA PEL: 50 ppm (105 mg/m3) TWA, 100 ppm (210 mg/m3) STEL

1993-1994 ACGIH TLV: 50 ppm (103 mg/m3) TWA, 100 ppm (207 mg/m3) STEL [skin]

Description of substance: Colorless gas with a faint, sweet odor which is not noticeable at dangerous concentrations.

LEL: . . . 8.1% (10% LEL, 8,100 ppm)

Original (SCP) IDLH: 10,000 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Patty [1963] that 20,000 to 40,000 ppm is dangerous to animals in 30 to 60 minutes [Flury and Zernik 1931] and the report by MacDonald [1964] that a worker repeatedly walked in and out of an area in which concentrations greater than 10,000 ppm were measured.

Short-term exposure guidelines: None developed

ACUTE TOXICITY DATA:

Lethal concentration data:

 

SpeciesReferenceLC50

(ppm)

LCLo

(ppm)

TimeAdjusted 0.5-hr

LC (CF)

Derived value
RatBakhishev 197572,000-----30 min72,000 ppm (1.0)7,200 ppm
MouseChellman et al. 1986 2,200-----6 hr5,060 ppm (2.3)506 ppm
MammalClayton & Clayton 1981 2,760-----4 hr5,520 ppm (2.0)552 ppm
G. pigClayton 1967-----20,0002 hr32,000 ppm (1.6)3,200 ppm
RatIzmerov et al. 1982 2,524-----4 hr5,048 ppm (2.0)505 ppm
Dogvon Oettingen 1949 ----- 14,6616 hr33,720 ppm (2.3) 3,372 ppm

Other animal data: It has been reported that 20,000 to 40,000 ppm is dangerous in 30 to 60 minutes [Flury and Zernik 1931].

Human data: It has been reported that a worker repeatedly walked in and out of an area in which concentrations greater than 10,000 ppm were measured; symptoms included blurring of vision, dizziness, and a slight headache [MacDonald 1964]. A worker exposed to concentrations of 2,000 to 4,000 ppm for 13 days stated that during the first week he was very sleepy and became quite dizzy; during the second week headache, blurring of vision, slurring of speech, dizziness, mental confusion, and a staggering gait occurred [MacDonald 1964]. Another worker exposed to concentrations of 1,000 to 2,000 ppm during the workshift experienced dizziness, blurring of vision, headache, nausea, and vomiting [MacDonald 1964]. It has been stated that exposures to 20,000 ppm for 2 hours may be fatal [Deichmann and Gerarde 1969].

 

Revised IDLH: 2,000 ppm

Basis for revised IDLH: The revised IDLH for methyl chloride is 2,000 ppm based on acute inhalation toxicity data in humans [MacDonald 1964]. [Note: NIOSH recommends as part of its carcinogen policy that the "most protective" respirators be worn for methyl chloride at any detectable concentration.]

REFERENCES:

1. Bakhishev GN [1975]. Relationship between chemical structure and toxicity for some halogenated aliphatic hydrocarbons. Fiz Akt Vesh 7:35-36 (in Russian).

2. Chellman GJ, White RD, Norton RM, Bus JS [1986]. Inhibition of the acute toxicity of methyl chloride in male B6C3F1 mice by glutathione depletion. Toxicol Appl Pharmacol 86:93-104.

3. Clayton GD, Clayton FE, eds. [1981]. Patty's industrial hygiene and toxicology. 3rd rev. ed. Vol. 2B. Toxicology. New York, NY: John Wiley & Sons, Inc., pp. 3436-3442.

4. Clayton JW Jr [1967]. Fluorocarbon toxicity and biological action. Fluor Chem Rev 1(2):197-252.

5. Deichmann WB, Gerarde HW [1969]. Methyl chloride. In: Toxicology of drugs and chemicals. New York, NY: Academic Press, Inc., pp. 386-387.

6. Flury F, Zernik F [1931]. Schädliche gase dämpfe, nebel, rauch- und staubarten. Berlin, Germany: Verlag von Julius Springer, p. 309 (in German).

7. Izmerov NF, Sanotsky IV, Sidorov KK [1982]. Toxicometric parameters of industrial toxic chemicals under single exposure. Moscow, Russia: Centre of International Projects, GKNT, p. 86.

8. MacDonald JDC [1964]. Methyl chloride intoxication: report of 8 cases. J Occup Med 6:82-83.

9. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1249.

10. von Oettingen WF [1949]. Studies on the relation between the toxic action of chlorinated methanes and their chemical and physicohemical properties. NIH Bulletin 191:1-85.

 
Contact Us:
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO