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Calcium arsenate (as As)

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

CAS number: 7778-44-1

NIOSH REL: 0.002 mg/m3 15-minute CEILING; NIOSH considers calcium arsenate to be a potential occupational carcinogen as defined by the OSHA carcinogen policy [29 CFR 1990].

Current OSHA PEL: 0.010 mg/m3 TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 0.01 mg/m3 TWA, A1

Description of Substance: Colorless to white, odorless solid.

LEL: Noncombustible Solid

Original (SCP) IDLH: 100 mg As/m3

Basis for original (SCP) IDLH: Because no data on acute inhalation toxicity are available for calcium arsenate, the chosen IDLH is based on an analogy with arsenic and compounds (as As) which has an IDLH of 100 mg As/m3.

Short-term exposure guidelines: None developed


Lethal dose data:

Species Reference Route LD50(mg/kg) LDLo(mg/kg) Adjusted LD Derived value




Back et al. 1972Lehman 1951

MacEwen and Vernot 1972

Muehlberger 1930

Perkow 1971/1976













2,103 mg As/m352 mg As/m3

2,056 mg As/m3

132 mg As/m3

98 mg As/m3

210 mg As/m35.2 mg As/m3

206 mg As/m3

13 mg As/m3

9.8 mg As/m3

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

Revised IDLH: 5 mg As/m3Basis for revised IDLH: No inhalation toxicity data are available on which to base an IDLH for calcium arsenate. Therefore, the revised IDLH for calcium arsenate is 5 mg As/m3 based on acute oral toxicity data in animals [Lehman 1951] and to be consistent with the revised IDLH for other inorganic arsenic compounds which have a revised IDLH of 5 mg As/m3. [Note: NIOSH recommends as part of its carcinogen policy that the “most protective” respirators be worn for calcium arsenate at concentrations above 0.002 mg As/m3. OSHA currently requires in 29 CFR 1919.1018 that workers be provided with and required to wear and use the “most protective” respirators in concentrations exceeding 20 mg As/m3 (i.e., 2,000 × the PEL).]



1. Back KC, Thomas AA, MacEwen JD [1972]. Reclassification of materials listed as transportation health hazards. Wright-Patterson Air Force Base, OH: 6570th Aerospace Medical Research Laboratory, Report No. TSA-20-72-3, pp. A-30 to A-31.

2. Lehman AJ [1951]. Chemicals in foods: a report to the Association of Food and Drug Officials on current developments. Part II. Pesticides. Q Bulletin Assoc Food Drug Off U.S. 15(4):122-125.

3. MacEwen JD, Vernot EH [1972]. Toxic Hazards Research Unit annual technical report: 1972. Wright-Patterson Air Force Base, OH: Aerospace Medical Research Laboratory, Report AMRL-TR-72-62.

4. Muehlberger CW [1930]. Toxicity studies of fluorine insecticides. J Pharmacol Exp Ther 39:246-248.

5. Perkow W [1971/1976]. Wirksubstanzen der Pflanzenschytz and Schadlingsbekampfungsmittel. Berlin, Germany: Verlag Paul Parey (in German).