Agent Name

Nitric acid

CAS Number

7697-37-2

Formula

H-N-O3

Major Category

Toxic Gases & Vapors

Synonyms

Acide nitrique [French]; Acido nitrico [Italian]; Acido nitrico [Spanish]; Acidum nitricum; Aqua fortis; Azotic acid; Azotowy kwas [Polish]; Engraver's acid; Hydrogen nitrate; Kyselina dusicne [Czech]; Nital; Nitric acid; Nitrous fumes; Nitryl hydroxide; RFNA; Red fuming nitric acid; Salpetersaeure; Salpetersaure [German]; Salpeterzuuroplossingen [Dutch]; [ChemIDplus] UN2031; UN2032

Category

Acids, Inorganic

Description

Colorless, yellow, or red, fuming liquid with an acrid, suffocating odor. [Note: Often used in an aqueous solution. Fuming nitric acid is concentrated nitric acid that contains dissolved nitrogen dioxide.]; [NIOSH]

Sources/Uses

Used primarily to produce ammonium nitrate fertilizer; also used in metal cleaning, etching, and manufacturing explosives; [ACGIH] Used as a wet etchant in semiconductor manufacturing at a standard concentration of 67%; [CSH, p. 46]

Comments

Liquid causes second or third degree burns after short contact; [CHRIS] Solutions >30% are highly corrosive to skin; Solutions <30% are corrosive; [Quick CPC] Nitrogen dioxide and nitric oxide are usually present as hazards whenever nitric acid is used. Occupational exposure may lead to acute pneumonitis and pulmonary edema. [ACGIH] May cause erosion of teeth enamel; [ICSC]

Exposure Assessment
Skin Designation (ACGIH)

Insufficient data

TIH

Yes

TLV (ACGIH)

2 ppm

STEL (ACGIH)

4 ppm

PEL (OSHA)

2 ppm

IDLH (NIOSH)

25 ppm

Excerpts from Documentation for IDLHs

Other animal data: Rats receiving a single exposure to 63 mg/m3 nitric acid (24 ppm) exhibited no apparent adverse effects [Diggle and Gage 1954].

Vapor Pressure

63.1 mm Hg

Odor Threshold Low

0.27 ppm

Lethal Concentration

LC50 (rat) = 67 ppm (NO2)/4H

Explanatory Notes

Odor threshold from AIHA; The Guide from the Emergency Response Guidebook is for "nitric acid, fuming."

Half Life

No reports found; [TDR, p. 937]

Adverse Effects
Toxic Pneumonitis

Yes

Dermatotoxin

Skin Burns

Links to Other NLM Databases
Health Studies

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Toxicity Information

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Chemical Information

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Biomedical References

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