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May 1994

Documentation for Immediately Dangerous To Life or Health Concentrations (IDLHs)


CAS number: 87–86–5

NIOSH REL: 0.5 mg/m3 TWA [skin]

Current OSHA PEL: 0.5 mg/m3 TWA [skin]

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 0.5 mg/m3 TWA [skin]

Description of substance: Colorless to white, crystalline solid with a benzene-like odor.

LEL: . . Noncombustible Solid

Original (SCP) IDLH: 150 mg/m3

Basis for original (SCP) IDLH: No useful data on acute inhalation toxicity are available on which to base the IDLH for pentachlorophenol. AIHA [1970] stated that the atmospheric concentration immediately hazardous to life is not known for humans, but painful irritation to the nose is observed at concentrations below those that would be immediately hazardous to life. The chosen IDLH, therefore, has been estimated from the smallest lethal intravenous dose in rabbits of 22 mg/kg [Kehoe et al. 1939 as cited by ACGIH 1971]. According to AIHA [1970], the cause of death from an acute overdose is hyperexia and cardiac failure [Patty 1963].

Short-term exposure guidelines: None developed


Lethal concentration data:


SpeciesReferenceLC50 LCLoTimeAdjusted 0.5-hr


Derived value
RatDemidenko 1969355 mg/m3-----???
MouseDemidenko 1969225 mg/m3-----???

Lethal dose data:






Adjusted LDDerived value





Borzelleca et al. 1985

Cabral et al. 1979

Deichmann et al. 1942

Deichmann et al. 1942

Fielder et al. 1982
















819 mg/m3

1,176 mg/m3

189 mg/m3

490 mg/m3

1,050 mg/m3

82 mg/m3

118 mg/m3

19 mg/m3

49 mg/m3

105 mg/m3

Human data: Dusts are particularly irritating to the eyes and nose at concentrations greater than 1 mg/m3 but concentrations up to 2.4 mg/m3 have been tolerated by workers that have been conditioned [Clayton and Clayton 1981]. It has been reported that 401 mg/kg is the minimum lethal oral dose [Haley 1977]. [Note: An oral dose of 401 mg/kg is equivalent to a worker being exposed to about 19,000 mg/m3 for 30 minutes, assuming a breathing rate of 50 liters per minute and 100% absorption.]


Revised IDLH: 2.5 mg/m3

Basis for revised IDLH: The revised IDLH for pentachlorophenol is 2.5 mg/m3 based on acute toxicity data in humans [Clayton and Clayton 1981]. This may be a conservative value due to the lack of relevant acute toxicity data for workers exposed to concentrations above 2.4 mg/m3.


1. ACGIH [1971]. Pentachlorophenol. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 198-199.

2. AIHA [1970]. Pentachlorophenol and sodium pentachlorophenate. In: Hygienic Guide Series. Am Ind Hyg Assoc J 31:521-524.

3. Borzelleca JF, Hayes JR, Condie LW, Egle JL Jr [1985]. Acute toxicity of monochlorophenols, dichlorophenols, and pentachlorophenols in the mouse. Toxicol Lett 29:39-42.

4. Cabral JRP, Raitano F, Mollner T, Bronczyk S, Shubik P [1979]. Acute toxicity of pesticides in hamsters. Toxicol Appl Pharmacol 48:A192 [Abstract].

5. Clayton GD, Clayton FE, eds. [1981]. Patty's industrial hygiene and toxicology. 3rd rev. ed. Vol. 2A. Toxicology. New York, NY: John Wiley & Sons, Inc., pp. 2604-2612.

6. Deichmann W, Machle W, Kitzmiller KV, Thomas G [1942]. Acute and chronic effects of pentachlorophenol and sodium pentachlorophenate upon experimental animals. J Pharmacol Exp Ther 76:104-117.

7. Demidenko NM [1969]. Data on the substantiation of the maximum permissible concentration of pentachlorophenol in air. Gig Tr Prof Zabol 13(9):58-60 (in Russian).

8. Fielder RJ, Sorrie GS, Bishop CM, Jones RB, Van Den Heuval MJ [1982]. Pentachlorophenol toxicity review 5. London, England: Health and Safety Executive, Her Majesty's Stationery Office.

9. Haley TJ [1977]. Human poisoning with pentachlorophenol and its treatment. Ecotoxicol Environ Safety 1:343-347.

10. Kehoe RA, Deichmann-Gruebler W, Kitzmiller KV [1939]. Toxic effect upon rabbits of pentachlorophenol and sodium pentachlorophenate. J Ind Hyg Toxicol 21(5):160-172.

11. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1400.

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