Ethyl mercaptan
May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 75–08–1
NIOSH REL: 0.5 ppm (1.3 mg/m3) 15-minute CEILING
Current OSHA PEL: 10 ppm (25 mg/m3) CEILING
1989 OSHA PEL: 0.5 ppm (1 mg/m3) TWA
1993-1994 ACGIH TLV: 0.5 ppm (1.3 mg/m3) TWA
Description of Substance: Colorless liquid with a strong, skunk-like odor.
LEL:. . 2.8% (10% LEL, 2,800 ppm)
Original (SCP) IDLH: 2,500 ppm
Basis for original (SCP) IDLH: The chosen IDLH is based on the mouse 4-hour LC50 of 2,770 ppm [Fairchild and Stokinger 1958 cited by ACGIH 1971].
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA
Lethal concentration data:
Species |
Reference |
LC50 (ppm) |
LCLo (ppm) |
Time |
Adjusted 0.5-hr LC (CF) |
Derived value |
| Rat Mouse |
Fairchild and Stokinger 1958 Fairchild and Stokinger 1958 |
4,420 2,770 |
----- ----- |
4 hr 4 hr |
8,840 ppm (2.0) 5,540 ppm (2.0) |
884 ppm 554 ppm |
Lethal dose data:
Species |
Reference |
Route |
LD50 (mg/kg) |
LDLo (mg/kg) |
Adjusted LD |
Derived value |
| Rat | Fairchild and Stokinger 1958 | oral | 682 | ----- | 1,849 ppm | 185 ppm |
Human data: None relevant for use in determining the revised IDLH.
| Revised IDLH: 500 ppm Basis for revised IDLH: The revised IDLH for ethyl mercaptan is 500 ppm based on acute inhalation toxicity data in animals [Fairchild and Stokinger 1958]. This may be a conservative value due to the lack of relevant acute toxicity data for workers. |
REFERENCES:
1. ACGIH [1971]. Ethyl mercaptan (ethanethiol). In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 107.
2. Fairchild EJ II, Stokinger HE [1958]. Toxicologic studies on organic sulfur compounds. I. Acute toxicity of some aliphatic and aromatic thiols (mercaptans). Am Ind Hyg Assoc J 19:171-189.