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METHYL ISOCYANATE†
| CAS # | 624-83-9 |
|---|---|
| Formula |
C₂H₃NO |
| Synonyms |
methyl ester of isocyanic acid; MIC; isocyanatomethane |
| Physical description | Colorless liquid with a sharp, pungent odor. | ||
|---|---|---|---|
| Boiling point | 102°F | Molecular weight | 57.05 |
| Freezing point/melting point | -112°F | Vapor pressure | 348 mmHg |
| Flash point | 19°F | Vapor density | |
| Specific gravity | 0.96 | Ionization potential | 10.67 eV |
| Lower explosive limit (LEL) | 5.3% | Upper explosive limit (UEL) | 26% |
| NFPA health rating | 4 | NFPA fire rating | 3 |
| NFPA reactivity rating | 2 | NFPA special instruction | W: Reacts violently or explosively with water. |
| Vapor hazard ratio (VHR) | |||
| Historical exceedance percentage | |||
| Target organs | |||
| Analyte code (IMIS no.) | 1773 |
|---|---|
| Sampling group | |
| Sampler/Sampling media | XAD-7 tube coated with 0.3 mg of 1-(2-pyridyl)piperazine (1-2PP) [No longer available] |
| Sampling time* | 300 min |
| Sampling volume (TWA)* |
15 L |
| Sampling flow rate (TWA)* |
0.05 L/min |
| Sampling volume (STEL/Peak/C)* | |
| Sampling flow rate (STEL/Peak/C)* | |
| Analytical method instruments | HPLC |
| Method reference | OSHA 54 (fully validated) |
| Notes |
This media is no longer available. OSHA staff please contact the SLTC prior to sampling at (801) 233-5100. |
| 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 Sampler/Sampling media | |
|---|---|
| Bulk Method |
| Device | Infrared spectrophotometer | Hazard Assessment Test Kit for Aliphatic Isocyanates | Photoionization Detector (PID) |
|---|---|---|---|
| Model/Type | Miran 1A & 1B | 769-1003 | |
|
Sampling information (see manufacturer instructions) |
0.1 ppm@4.4 µm | Isocyanate Surface and Dermal Sampling, Hazard Assessment Test Kit for Aliphatic Isocyanates |
|
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 |
|||||
|---|---|---|---|---|---|---|---|
| PEL-TWA |
0.02 ppm (0.05 mg/m³) |
REL-TWA |
0.02 ppm (0.05 mg/m³) |
TLV-TWA |
0.02 ppm [2013] |
PEL-TWA |
0.02 ppm (0.05 mg/m³) |
| PEL-STEL | REL-STEL | TLV-STEL |
0.06 ppm [2013] |
PEL-STEL | |||
| PEL-C | REL-C | TLV-C | PEL-C | ||||
| Skin notation |
Y |
Skin notation |
Y |
Skin notation |
Y |
Skin notation |
Y |
| Notes: | Notes: |
Notes:
dermal sensitization (DSEN) |
Notes: | ||||
| Health factors: See NIH-NLM PubChem. | IDLH |
3 ppm |
|||||
| Carcinogenic classifications: Not listed | Notes: | ||||||
|
AIHA emergency response planning guidelines - ERPG-1/ERPG-2/ERPG-3:
0.025 ppm/0.25 ppm/1.5 ppm |
|||||||
Additional Resources and Literature References
|
NOAA: CAMEO Chemicals - Methyl isocyanate NIOSH: Pocket Guide to Chemical Hazards - Methyl isocyanate Literature References
|
Last Updated Date : 04/02/2025