| Agent Name |
Methyl mercaptan |
|---|
| Alternative Name |
Methanethiol |
|---|
| CAS Number |
74-93-1 |
|---|
| Formula |
C-H4-S |
|---|
| Major Category |
Toxic Gases & Vapors |
|---|
| Synonyms |
Mercaptomethane; Methyl sulfhydrate; Methanethiol; Thiomethanol; Thiomethyl alcohol; [ChemID] UN1064 |
|---|
| Category |
Other Toxic Gases & Vapors |
|---|
| Description |
Colorless gas with a disagreeable odor like garlic or rotten cabbage; Note: A liquid below 43 degrees F. Shipped as a liquefied compressed gas; [NIOSH] |
|---|
| Sources/Uses |
Used as an odorant for some gases which are hazardous and odorless; used in the production of pesticides, jet fuel, plastics, and other organic chemicals; methyl mercaptan is a byproduct of the Kraft or sulfate process in paper and pulp production; [ACGIH] Produced from decaying organic matter and by pulp mills and oil refineries; [CAMEO] |
|---|
| Comments |
A pulmonary irritant that can cause pulmonary edema after inhalation of high concentrations; Liver injury has been documented after occupational exposure. In high concentrations methyl mercaptan can cause coma and death, acting as a chemical asphyxiant similar to hydrogen sulfide. [ACGIH] Methemoglobinemia has been reported after occupational exposure. [HSDB] Possible frostbite from contact with liquid; [NIOSH] |
|---|
| Reference Link |
ATSDR Medical Management - Methyl Mercaptan |
|---|
| Exposure Assessment |
|---|
| Skin Designation (ACGIH) |
No |
|---|
| TIH |
Yes |
|---|
| TLV (ACGIH) |
0.5 ppm |
|---|
| PEL (OSHA) | Ceiling(OSHA) = 10 ppm |
|---|
| MAK |
0.5 ppm |
|---|
| IDLH (NIOSH) |
150 ppm |
|---|
| Excerpts from Documentation for IDLHs |
Human data: Students accidentally exposed to about 4 ppm for several hours experienced headaches and nausea [Clayton and Clayton 1981]. Some investigators have reported that the toxicity of methyl mercaptan is similar to hydrogen sulfide while others report the toxicity to be somewhat less than hydrogen sulfide [DeRekowski 1893; Frankel 1921]. |
|---|
| Odor Threshold Low |
2 x 10 -07 ppm |
|---|
| Odor Threshold High |
0.04 ppm |
|---|
| Lethal Concentration |
LC50 (rats) = 675 ppm |
|---|
| Explanatory Notes |
Detection odor threshold from AIHA (mean = 0.00054 ppm); Flash point = -18 deg C; |
|---|
| Half Life |
No reports found; [TDR, p. 893] |
|---|
| Reference Link |
International Chemical Safety Cards (WHO/IPCS/ILO) |
|---|
| Flammability (NFPA) |
4: burns readily |
|---|
| Adverse Effects |
|---|
| Toxic Pneumonitis |
Yes |
|---|
| Methemoglobinemia |
Methemoglobinemia, Secondary |
|---|
| Hepatotoxin |
Hepatotoxin, Secondary |
|---|
| Other Poison |
Chemical Asphyxiant |
|---|
| Links to Other NLM Databases |
|---|
| Health Studies |
Human Health Effects from Hazardous Substances Data Bank: METHYL MERCAPTAN
|
|---|
