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Perchloromethyl mercaptan

May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)

CAS number: 594–42–3

NIOSH REL: 0.1 ppm (0.8 mg/m3) TWA

Current OSHA PEL: 0.1 ppm (0.8 mg/m3) TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 0.1 ppm (0.76 mg/m3) TWA

Description of substance: Pale-yellow, oily liquid with an unbearable, acrid odor.

LEL: . . Noncombustible Liquid

Original (SCP) IDLH: 10 ppm

Basis for original (SCP) IDLH: No useful data on acute inhalation toxicity are available on which to base the IDLH for perchloromethyl mercaptan. The chosen IDLH, therefore, has been based on an analogy with hydrogen sulfide. According to ACGIH, perchloromethyl mercaptan is about 20 times more toxic than hydrogen sulfide which has an IDLH of 300 ppm.

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50(ppm) LCLo(ppm) Time Adjusted 0.5-hrLC (CF) Derived value






Althoff 1973Althoff 1973

Althoff 1973

Flury &Zernik 1931

Izmerov et al. 1982

Marhold 1972

Vernot et al. 1977













1 hr1 hr

3 hr

10 min

2 hr

15 min

1 hr

14 ppm (1.25)20 ppm (1.25)

16 ppm (1.8)

268 ppm (0.69)

61 ppm (1.6)

36 ppm (0.79)

14 ppm (1.25)

1.4 ppm2.0 ppm

1.6 ppm

27 ppm

6.1 ppm

3.6 ppm

1.4 ppm

Lethal dose data:

Species Reference Route LD50(mg/kg) LDLo(mg/kg) Adjusted LD Derived value
Rat Marhold 1972 oral 82.6 —– 75 ppm 7.5 ppm

Other human data: It has been stated that perchloromethyl mercaptan is about one-sixth as toxic as phosgene [Prentiss 1937].


1. ACGIH [?].

2. Althoff H [1973]. Todliche perchlormethylmercaptan-intoxikation. Arch Toxikol 31:121-134. [From ACGIH [1991]. Perchloromethyl mercaptan. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 1195-1196.]

3. Flury F, Zernik F [1931]. Schädliche gase dämpfe, nebel, rauch- und staubarten. Berlin, Germany: Verlag von Julius Springer, p. 362 (in German).

4. Izmerov NF, Sanotsky IV, Sidorov KK [1982]. Toxicometric parameters of industrial toxic chemicals under single exposure. Moscow, Russia: Centre of International Projects, GKNT, p. 97.

5. Marhold JV [1972]. Sbornik vysledku toxixologiekeho vysetreni latek a pripravku. Prague, Czechoslovakia: Institut Prumyclu, p. 13 (in Czechoslovakian).

6. Prentiss AM [1937]. Chemicals in war. A treatise on chemical warfare. New York, NY: McGraw-Hill Book Company, Inc., p. 154.

7. Vernot EH, MacEwen JD, Haun CC, Kinkead ER [1977]. Acute toxicity and skin corrosion data for some organic and inorganic compounds and aqueous solutions. Toxicol Appl Pharmacol 42(2):417-423.