Agent Name

Osmium tetroxide

CAS Number

20816-12-0

Formula

O4-Os

Major Category

Metals

Synonyms

Osmic acid; Osmic acid anhydride; Osmium tetraoxide; Osmium tetroxide; Perosmic acid anhydride; Perosmic oxide; [ChemIDplus] UN2471

Category

Metals, Inorganic Compounds

Description

Colorless, crystalline solid or pale-yellow mass with an unpleasant, acrid, chlorine-like odor; Note: A liquid above 105 degrees F; [NIOSH]

Sources/Uses

Used primarily for staining of biological and pathological tissues for microscopic study; [ACGIH]

Comments

A skin and respiratory irritant, OsO4 can cause pulmonary edema in animals exposed to high concentrations. [ACGIH] A lachrymator; [ChemFinder] "Tear drawing" and corrosive to the skin, eyes, and respiratory tract; May cause kidney injury after prolonged or repeated exposure; [ICSC] Osmium tetroxide can cause chronic bronchitis. [LaDou, p. 330] May cause severe burns; [CAMEO] Based on animal studies, osmium tetroxide bioaccumulates after chronic exposure and may cause kidney and liver damage. [HSDB] See "Osmium."

Exposure Assessment
Skin Designation (ACGIH)

Insufficient data

Bioaccumulates

Yes

STEL (ACGIH)

0.0047 mg/m3

PEL (OSHA)

0.002 mg/m3, as Os

IDLH (NIOSH)

1 mg/m3, as Os

Excerpts from Documentation for IDLHs

It has been suggested that 1 mg/m3 is tolerable for 30 minutes [Flury and Zernik 1931]. Workers exposed to 0.1 to 0.6 mg/m3 suffered from lacrimation and disturbances of vision and in some cases, headache, conjunctivitis, and cough [McLaughlin et al. 1946].

Vapor Pressure

7 mm Hg

Odor Threshold Low

0.0019 mg/m3

Lethal Concentration

LCLo (rat) = 40 ppm/4H

Explanatory Notes

Odor threshold from NJ "Hazardous Substance Fact Sheet";

Reference Link

ICSC: Osmium tetroxide

Adverse Effects
Nephrotoxin

Yes

Lacrimator

Yes

Chronic Bronchitis

Yes

Toxic Pneumonitis

Yes

Hepatotoxin

Hepatotoxin, Secondary

Dermatotoxin

Skin Burns

Links to Other NLM Databases
Health Studies

Human Health Effects from Hazardous Substances Data Bank:

Toxicity Information

Chemical Information

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Related Information in HazMap
Diseases

Occupational diseases associated with exposure to this agent: