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Registry of Toxic Effects of Chemical Substances (RTECS)

Isocyanic acid, methyl ester

RTECS #

NQ9450000

CAS #

624-83-9

Updated

September 201

Molecular Weight

57.06

Molecular Formula

C2H3NO

Synonyms

Isocyanate de methyle (French)
Iso-cyanatomethane
Methyl isocyanat (German)
Methyl isocyanate
Methyl isocyanate (ACGIH:OSHA)
Methylisocyanaat (Dutch)
Methylisokyanat (Czech)
Metil isocianato (Italian)
RCRA waste number P064
TL 1450

Skin and Eye Irritation and References

Route/OrganismDoseEffectReference
eye /rabbit 5 µL/24H severeNTIS** OTS0529151
skin /rabbit 10 µL/24H moderateNTIS** OTS0529151

Mutation Data and Reference

System TestRoute/Organism/TissueDoseReference
Cytogenetic Analysisinhalation/mouse3 ppm/6H/4D-continuousENMUDM 9,37,1987
Cytogenetic Analysisovary/hamster10100 µg/LENMUDM 9,19,1987
micronucleus testinhalation/mouse6 ppm/6H/4D-continuousENMUDM 9,37,1987
mutation in mammalian somatic cellslymphocyte/mouse8 µmol/LMUREAV 174,285,1986
mutation in microorganisms/Salmonella typhimurium50 µg/plate (+enzymatic activation step)IJEBA6 25,548,1987
mutation in microorganisms/Salmonella typhimurium100 µg/plate (-enzymatic activation step)MUREAV 204,123,1988
other mutation test systems/Escherichia coli1 µmol/plateMUREAV 283,97,1992
other mutation test systemsinhalation/mouse3 ppm/6H/4D-continuousENMUDM 9,29,1987
sister chromatid exchangeovary/hamster900 µg/LENMUDM 9,19,1987
sister chromatid exchangeinhalation/mouse1 ppm/6H/4D-continuousENMUDM 9,29,1987

Reproductive Effects Data and References

Route/OrganismDoseEffectReference
inhalation/rat 9 ppm/3H (10D pregnant)Reproductive: Effects on fertility: Post- implantation mortality (e.g., dead and/or resorbed implants per total number of implants)

Reproductive: Effects on embryo or fetus: Fetotoxicity (except death, e.g., stunted fetus)		JTEHD6 30,1,1990
inhalation/mouse 9 ppm/3H (8D pregnant)Reproductive: Effects on fertility: Post- implantation mortality (e.g., dead and/or resorbed implants per total number of implants)

Reproductive: Effects on embryo or fetus: Fetotoxicity (except death, e.g., stunted fetus)		JTEHD6 30,1,1990
inhalation/mouse 9 ppm/3H (8D pregnant)Reproductive: Effects on fertility: Litter size (e.g., # fetuses per litter; measured before birth)

Reproductive: Effects on embryo or fetus: Extra embryonic structures (e.g., placenta, umbilical cord)

Reproductive: Specific developmental abnormalities: Musculoskeletal system		JTEHD6 21,265,1987
inhalation/mouse 9 ppm/3H (1D pregnant)Reproductive: Other effects on male

Reproductive: Effects on fertility: Mating performance (e.g., # sperm positive females per # females mated; # copulations per # estrus cycles)		JTEHD6 21,265,1987
inhalation/mouse 1 ppm/6H (14-17D pregnant)Reproductive: Effects on newborn: StillbirthEVHPAZ 72,149,1987
inhalation/mouse 3 ppm/6H (14-17D pregnant)Reproductive: Effects on newborn: Viability index (e.g., # alive at day 4 per # born alive)

Reproductive: Effects on newborn: Weaning or lactation index (e.g., # alive at weaning per # alive at day 4)		EVHPAZ 72,149,1987

Acute Toxicity Data and References

Route/OrganismDoseEffectReference
inhalation/guinea pig lethal concentration (50 percent kill): 5400 ppb/6HEye: Lacrimation

Lung, Thorax, or Respiration: Dyspnea		FAATDF 6,747,1986
inhalation/human lowest published toxic concentration: 2 ppmOlfaction: Other olfaction effects

Eye: Conjunctiva irritation

Lung, Thorax, or Respiration: Other changes		ATXKA8 20,235,1964
inhalation/mouse lethal concentration (50 percent kill): 12200 ppb/6HEye: Lacrimation

Lung, Thorax, or Respiration: Dyspnea		FAATDF 6,747,1986
inhalation/rat lethal concentration (50 percent kill): 6100 ppb/6HEye: Lacrimation

Lung, Thorax, or Respiration: Dyspnea		FAATDF 6,747,1986
oral/mouse lethal dose (50 percent kill): 120 mg/kgTXAPA9 42,417,1977
oral/rat lethal dose (50 percent kill): 71 mg/kgTOXID9 -,170,2009
oral/rat lethal dose (50 percent kill): 51500 µg/kgPeripheral Nerve and Sensation: Flaccid paralysis without anesthesia (usually neuromuscular blockage)

Behavioral: Somnolence (general depressed activity)

Lung, Thorax, or Respiration: Respiratory depression		IJEBA6 25,531,1987
skin/mouse lethal dose (50 percent kill): 1820 mg/kgYKYUA6 38,391,1987
skin/rabbit lethal dose (50 percent kill): 220 µL/kgSkin: After systemic exposure: Dermatitis, otherNTIS** OTS0529151
skin/rat lethal dose (50 percent kill): 2780 mg/kgYKYUA6 38,391,1987
subcutaneous/mouse lethal dose (50 percent kill): 81900 µg/kgPeripheral Nerve and Sensation: Flaccid paralysis without anesthesia (usually neuromuscular blockage)

Behavioral: Somnolence (general depressed activity)

Lung, Thorax, or Respiration: Respiratory depression		IJEBA6 25,531,1987
subcutaneous/rabbit lethal dose (50 percent kill): 126 mg/kgTXCYAC 51,223,1988
subcutaneous/rat lethal dose (50 percent kill): 261 mg/kgPeripheral Nerve and Sensation: Flaccid paralysis without anesthesia (usually neuromuscular blockage)

Behavioral: Somnolence (general depressed activity)

Lung, Thorax, or Respiration: Respiratory depression		IJEBA6 25,531,1987

Other Multiple Dose Data and References

Route/OrganismDoseEffectReference
inhalation/mouse lowest published toxic concentration: 3 ppm/6H/4D- intermittentOlfaction: Other olfaction effects

Lung, Thorax, or Respiration: Structural or functional change in trachea or bronchi

Related to Chronic Data: Death in the "MULTIPLE DOSE" data type field		FAATDF 9,480,1987
inhalation/rat lowest published toxic concentration: 3 ppm/6H/4D- intermittentLung, Thorax, or Respiration: Fibrosis, focal (pneumoconiosis)

Endocrine: Other changes

Nutritional and Gross Metabolic: Weight loss or decreased weight gain		FAATDF 9,480,1987
inhalation/rat lowest published toxic concentration: 3 ppm/6H/8D- intermittentLung, Thorax, or Respiration: Changes in lung weight

Blood: Pigmented or nucleated red blood cells

Nutritional and Gross Metabolic: Weight loss or decreased weight gain		EVHPAZ 72,117,1987
inhalation/rat lowest published toxic concentration: 3070 ppb/6H/8D- intermittentBehavioral: Food intake (animal)

Liver: Changes in liver weight

Nutritional and Gross Metabolic: Weight loss or decreased weight gain		NTIS** OTS0535177

Reviews

OrganizationStandardReference
American Conference of Governmental Industrial Hygienists (ACGIH)Threshold Limit Value-time-weighted average 0.02 ppm (skin)DTLVS* TLV/BEI,2013
TOXICOLOGY REVIEWDIMON* 46,551,2000
TOXICOLOGY REVIEWENTOX* -,81,2005
TOXICOLOGY REVIEWTOPADD 33,517,2005
TOXICOLOGY REVIEWHUTOX* -,661,1996
TOXICOLOGY REVIEWHTCWA* 2,293,
TOXICOLOGY REVIEWCCACL* 21,691,2005
TOXICOLOGY REVIEWMUREAV 721,27,2011

Standards and Regulations

OrganizationStandardReference
Mine Safety and Health Administration (MSHA) STANDARD-airtime-weighted average 0.02 ppm (0.05 mg/m3) (skin)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 0.02 mg(NCO)/m3, short term exposure limit 0.07 mg(NCO)/m3, JUL2008
Occupational Exposure Limit-AUSTRIAMAK-TMW 0.01 ppm (0.024 mg/m3);KZW 0.01 ppm (0.024 mg/m3), skin, sen, 2007
Occupational Exposure Limit-BELGIUMtime-weighted average 0.02 ppm (0.048 mg/m3), Skin, MAR2002
Occupational Exposure Limit-DENMARKceiling concentration 0.01 ppm (0.03 mg/m3), skin, MAY2011
Occupational Exposure Limit-FINLANDshort term exposure limit 0.02 ppm (0.05 mg/m3), skin, NOV2011
Occupational Exposure Limit-FRANCEVME 0.02 ppm (0.05 mg/m3), Skin, FEB2006
Occupational Exposure Limit-GERMANYMAK 0.01 ppm (0.024 mg/m3), 2011
Occupational Exposure Limit-HUNGARYtime-weighted average 0.024 mg/m3, short term exposure limit 0.024 mg/m3, Skin, SEP2000
Occupational Exposure Limit-ICELANDshort term exposure limit 0.01 ppm (0.03 mg/m3), skin, NOV2011
Occupational Exposure Limit-KOREAtime-weighted average 0.02 ppm (0.05 mg/m3), skin, 2006
Occupational Exposure Limit-MEXICOtime-weighted average 0.02 ppm (0.05 mg/m3), 2004
Occupational Exposure Limit-NEW ZEALANDtime-weighted average 0.02 ppm (0.047 mg/m3), skin, JAN2002
Occupational Exposure Limit-NORWAYtime-weighted average 0.005 ppm (0.015 mg/m3), JAN1999
Occupational Exposure Limit-PERUtime-weighted average 0,02 ppm (0,047 mg/m3), JUL2005
Occupational Exposure Limit-RUSSIAshort term exposure limit 0.05 mg/m3, Skin, JUN2003
Occupational Exposure Limit-SWEDENtime-weighted average 0.01 ppm (0.024 mg/m3), ceiling concentration 0.02 ppm (0.047 mg/m3), JUN2005
Occupational Exposure Limit-SWITZERLANDceiling concentration 0.02 mg(NCO)/m3, sen, JAN2011
Occupational Exposure Limit-THE NETHERLANDSMAC-TGG 0.05 mg/m3, Skin, 2003
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Construction)8H time-weighted average 0.02 ppm (0.05 mg/m3) (skin)CFRGBR 29,1926.55,1994
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Federal Contractors)8H time-weighted average 0.02 ppm (0.05 mg/m3) (skin)CFRGBR 41,50-204.50,1994
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (General Industry)8H time-weighted average 0.02 ppm (0.05 mg/m3) (skin)CFRGBR 29,1910.1000,1994
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Shipyards)8H time-weighted average 0.02 ppm (0.05 mg/m3) (skin)CFRGBR 29,1915.1000,1993

NIOSH Documentation and Surveillance

OrganizationStandardReference
National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Level TO METHYL ISOCYANATE-air10H time-weighted average 0.02 ppm (Sk)NIOSH* DHHS #92-100,1992
National Occupational Exposure Survey 1983Hazard Code 47625; Number of Industries 1; Total Number of Facilities 7; Number of Occupations 1; Total Number of Employees Exposed 1822; Total Number of Female Employees Exposed 272
National Occupational Hazard Survey 1974Hazard Code 47625; Number of Industries 2; Total Number of Facilities 56; Number of Occupations 3; Total Number of Employees Exposed 2381

Status in Federal Agencies

OrganizationReference
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
On EPA IRIS database
OSHA ANALYTICAL METHOD #54

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