Heptachlor

CAS number: 76–44–8

NIOSH REL: 0.5 mg/m³ TWA [skin]; NIOSH considers heptachlor to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990].

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: White to light-tan crystals with a camphor-like odor.

LEL:. . Noncombustible Solid

Original (SCP) IDLH: 700 mg/m³

Basis for original (SCP) IDLH: No data on acute inhalation toxicity are available on which to base the IDLH for heptachlor. The chosen IDLH, therefore, has been estimated from the male rat oral LD₅₀ of 100 mg/kg [Gaines 1960 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
Cat Mammal	Izmerov et al. 1982 Osetrov 1958	----- -----	150 mg/m3 200 mg/m3	4 hr 4 hr	300 mg/m3 (2.0) 400 mg/m3 (2.0)	30 mg/m3 40 mg/m3

Lethal dose data:

Species	Reference	Route	LD50 (mg/kg)	LDLo (mg/kg)	Adjusted LD	Derived value
G. pig Rat Rat Mouse Cat Hamster	AAPCO 1966 Edson 1960 Gaines 1960 Kenaga and Morgan 1978 Osetrov 1958 Truhaut et al. 1974	oral oral oral oral oral oral	116 40 100 68 ----- 100	----- ----- ----- ----- 50 -----	812 mg/m3 280 mg/m3 700 mg/m3 476 mg/m3 350 mg/m3 700 mg/m3	81 mg/m3 28 mg/m3 70 mg/m3 48 mg/m3 35 mg/m3 70 mg/m3

Human data: None relevant for use in determining the revised IDLH.

Revised IDLH: 35 mg/m3 Basis for revised IDLH: The revised IDLH for heptachlor is 35 mg/m3 based on acute inhalation toxicity data in animals [Izmerov et al. 1982; Osetrov 1958]. [Note: NIOSH recommends as part of its carcinogen policy that the "most protective" respirators be worn for heptachlor at concentrations above 0.5 mg/m3.]

REFERENCES:

1. AAPCO [1966]. Pesticide chemicals official compendium. Topeka, KS: Association of the American Pesticide Control Officials, Inc. p. 576.

2. ACGIH [1971]. Heptachlor. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 123-124.

3. Edson EF [1960]. Applied toxicology of pesticides. Pharmaceut J 185:361-367.

4. Gaines TB [1960]. The acute toxicity of pesticides to rats. Toxicol Appl Pharmacol 2:88-99.

5. Izmerov NF, Sanotsky IV, Sidorov KK [1982]. Toxicometric parameters of industrial toxic chemicals under single exposure. Moscow, Russia: Centre of International Projects, GKNT, p. 71.

6. Kenaga EE, Morgan RW [1978]. Commercial and experimental organic insecticides. Entomological Society of America Special Publication 78-1:12.

7. Osetrov VE [1958]. Experimental data on toxicology of the insecticide heptachlor. Gig Tr Prof Zabol 2(5):15 (in Russian).

8. Truhaut R, Gak JC, Graillot C [1974]. Recherches sur les modalités et les mécanismes d'action toxique des insecticides organochlorés. I. Étude comparative des effets de toxicité aiguë chez le hamster et chez le rat. J Eur Toxicol 7(3):159-166 (in French).