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Methanethiol

Related Pages
RTECS #
PB4375000
CAS #
74-93-1
See: NMAM or OSHA Methods
Updated
December 2018
Molecular Weight
48.11
Molecular Formula
CH4S
Synonyms
Mercaptan methylique (French)
Mercaptomethane
Methaanthiol (Dutch)
Methanethiol (OSHA)
Methanthiol (German)
Methvtiolo (Italian)
Methyl mercaptan
Methyl mercaptan (ACGIH:OSHA)
Methylmercaptaan (Dutch)
Metilmercaptano (Italian)
RCRA waste number U153
Thiomethanol
Thiomethyl alcohol

Mutation Data and Reference

System TestRoute/Organism/TissueDoseReference
sex chromosome loss and nondisjunctioninhalation/Drosophila melanogaster99 pph/6M-continuousENVRAL 7,286,1974

Acute Toxicity Data and References

Route/OrganismDoseEffectReference
inhalation/mouse lethal concentration (50 percent kill): 6530 µg/m3/2HGTPZAB 16(6),46,1972
inhalation/rat lethal concentration (50 percent kill): 675 ppmLung, Thorax, or Respiration: Other changes

Gastrointestinal: Hypermotility, diarrhea

Kidney, Ureter, and Bladder: Urine volume increased		LacHB# 09JUN1978
inhalation/rat lethal concentration (50 percent kill): 643 ppm/4HHPV297 -,-,2001
inhalation/rat lethal concentration (50 percent kill): 1428 ppm/1HBehavioral: Ataxia

Lung, Thorax, or Respiration: Dyspnea		HPV297 -,-,2001
inhalation/rat lowest published toxic concentration: 700 ppm/30MBehavioral: Somnolence (general depressed activity)HPV297 -,-,2001
inhalation/rat lowest published toxic concentration: 1500 ppm/30MBehavioral: Somnolence (general depressed activity)

Behavioral: Tremor		HPV297 -,-,2001
inhalation/rat Lowest published lethal concentration: 10000 ppm/30MBehavioral: Somnolence (general depressed activity)

Behavioral: Convulsions or effect on seizure threshold

Lung, Thorax, or Respiration: Acute pulmonary edema		HPV297 -,-,2001
unreported route/mammal (species unspecified) lethal dose (50 percent kill): 60670 µg/kgGTPZAB 16(6),46,1972

Other Multiple Dose Data and References

Route/OrganismDoseEffectReference
inhalation/rat lowest published toxic concentration: 17 ppm/7H/13W- intermittentEndocrine: Changes in adrenal weight

Endocrine: Changes in spleen weight

Blood: Changes in serum composition (e.g. TP, bilirubin, cholesterol)		JTEHD6 8,71,1981
inhalation/rat lowest published toxic concentration: 100 ppm/6H/3D- intermittentBehavioral: Excitement

Lung, Thorax, or Respiration: Fibrosis, focal (pneumoconiosis)

Nutritional and Gross Metabolic: Other changes		NTIS** OTS0571484
inhalation/rat lowest published toxic concentration: 57 ppm/12W- intermittentLiver: Other changes

Nutritional and Gross Metabolic: Weight loss or decreased weight gain

Biochemical: Enzyme inhibition, induction, or change in blood or tissue levels: Dehydrogenases		HPV297 -,-,2001

Reviews

OrganizationStandardReference
American Conference of Governmental Industrial Hygienists (ACGIH)Threshold Limit Value-time-weighted average 0.5 ppmDTLVS* TLV/BEI,2013
TOXICOLOGY REVIEWRTOPDW 54,247,2009

Standards and Regulations

OrganizationStandardReference
Mine Safety and Health Administration (MSHA) STANDARD-airtime-weighted average 0.5 ppm (1 mg/m3)DTLVS* 3,167,1971
Occupational Exposure Limit IN ARGENTINA, BULGARIA, COLOMBIA, JORDAN check ACGIH TLV;
Occupational Exposure Limit IN SINGAPORE, VIETNAM check ACGIH TLV
Occupational Exposure Limit-AUSTRALIAtime-weighted average 0.5 ppm (0.98 mg/m3), JUL2008
Occupational Exposure Limit-AUSTRIAMAK-TMW 0.5 ppm (1 mg/m3);KZW 0.5 ppm (1 mg/m3), 2007
Occupational Exposure Limit-BELGIUMtime-weighted average 0.5 ppm (0.99 mg/m3), MAR2002
Occupational Exposure Limit-DENMARKtime-weighted average 0.5 ppm (1 mg/m3), MAY2011
Occupational Exposure Limit-FINLANDtime-weighted average 0.5 ppm (1 mg/m3), short term exposure limit 1.5 ppm (3 mg/m3), NOV2011
Occupational Exposure Limit-FRANCEVME 0.5 ppm (1 mg/m3), FEB2006
Occupational Exposure Limit-GERMANYMAK 0.5 ppm (1 mg/m3), 2011
Occupational Exposure Limit-HUNGARYtime-weighted average 1 mg/m3, short term exposure limit 1 mg/m3, SEP2000
Occupational Exposure Limit-ICELANDtime-weighted average 0.5 ppm (1 mg/m3), NOV2011
Occupational Exposure Limit-KOREAtime-weighted average 0.5 ppm (1 mg/m3), 2006
Occupational Exposure Limit-MEXICOtime-weighted average 0.5 ppm (1 mg/m3), 2004
Occupational Exposure Limit-NEW ZEALANDtime-weighted average 0.5 ppm (0.98 mg/m3), JAN2002
Occupational Exposure Limit-NORWAYtime-weighted average 0.5 ppm (1 mg/m3), JAN1999
Occupational Exposure Limit-PERUtime-weighted average 0,5 ppm (1 mg/m3), JUL2005
Occupational Exposure Limit-POLANDMAC(time-weighted average) 1 mg/m3, MAC(short term exposure limit) 2 mg/m3, JAN1999
Occupational Exposure Limit-RUSSIAshort term exposure limit 0.8 mg/m3, JUN2003
Occupational Exposure Limit-SWEDENtime-weighted average 1 ppm, JUN2005
Occupational Exposure Limit-SWITZERLANDMAK-week 0.5 ppm (1 mg/m3), KZG-week 1 ppm (2 mg/m3), JAN2011
Occupational Exposure Limit-THAILANDtime-weighted average 10 ppm (20 mg/m3), JAN1993
Occupational Exposure Limit-THE NETHERLANDSMAC-TGG 1 mg/m3, 2003
Occupational Exposure Limit-THE PHILIPPINEStime-weighted average 10 ppm (20 mg/m3), JAN1993
Occupational Exposure Limit-TURKEYtime-weighted average 10 ppm (20 mg/m3), JAN1993
Occupational Exposure Limit-UNITED KINGDOMtime-weighted average 0.5 ppm (1 mg/m3), OCT2007
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Construction)8H time-weighted average 0.5 ppm (1 mg/m3)CFRGBR 29,1926.55,1994
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Federal Contractors)ceiling concentration 10 ppm (20 mg/m3)CFRGBR 41,50-204.50,1994
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (General Industry)ceiling concentration 10 ppm (20 mg/m3)CFRGBR 29,1910.1000,1994
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Shipyards)8H time-weighted average 0.5 ppm (1 mg/m3)CFRGBR 29,1915.1000,1993

NIOSH Documentation and Surveillance

OrganizationStandardReference
National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Level TO METHANETHIOL-airceiling concentration 0.5 ppm/15MNIOSH* DHHS #92-100,1992
National Occupational Exposure Survey 1983Hazard Code 45850; Number of Industries 7; Total Number of Facilities 147; Number of Occupations 25; Total Number of Employees Exposed 6192; Total Number of Female Employees Exposed 380
National Occupational Hazard Survey 1974Hazard Code 45850; Number of Industries 1; Total Number of Facilities 11; Number of Occupations 3; Total Number of Employees Exposed 357

Status in Federal Agencies

OrganizationReference
ATSDR TOXICOLOGY PROFILE (NTIS** PB/93/110799/AS)
EPA TSCA Section 8(b) CHEMICAL INVENTORY
EPA TSCA Section 8(d) unpublished health/safety studies
EPA TSCA TEST SUBMISSION (TSCATS) DATA BASE, JANUARY 2001
NIOSH Analytical Method, 1994: Mercaptans, 2542
On EPA IRIS database
OSHA ANALYTICAL METHOD #26
Page last reviewed: November 16, 2018
Content source: National Institute for Occupational Safety and Health