Agent Name |
Phosphoric acid |
CAS Number |
7664-38-2 |
Formula |
H3-O4-P |
Major Category |
Other Classes |
Synonyms |
Acide phosphorique [French]; Acido fosforico [Italian]; Acidum phosphoricum; Evits; Fosforzuuroplossingen [Dutch]; Hydrogen phosphate; Orthophosphoric acid; Phosphoric acid; Phosphoric acid, ortho-; Phosphorsaeure; Phosphorsaeureloesungen [German]; Sonac; Wc-reiniger; White phosphoric acid; o-Phosphoric acid; [ChemIDplus] UN1805 |
Category |
Phosphorus Compounds |
Description |
Thick, colorless, odorless, crystalline solid. [Note: Often used in an aqueous solution.]; [NIOSH] |
Sources/Uses |
". . . used in fertilizers, detergents, foods and beverages, water treatment, pickling and rust proofing metals, and for many other purposes." [ACGIH] Used in photography (platinum printing); [www.ci.tucson.az.us/arthazards/medium.html] |
Comments |
Liquid or solid form causes second degree burns after contact for a few minutes; [CHRIS] Usually shipped as a solid or 85% solution. [CAMEO] Phosphoric acid > 70% is corrosive to skin. [Quick CPC] Phosphoric acid is an eye, skin, and upper respiratory tract irritant. [ACGIH] "The risk of pulmonary edema is very small." [Desai H. Phosphorus and Phosphorus Compounds. In: Sullivan JB, Krieger GR (eds). Hazardous Materials Toxicology. Baltimore: Williams & Wilkins, 1992; p. 938.] Corrosive to the skin, eye, and respiratory tract; [ICSC] |
Exposure Assessment |
Skin Designation (ACGIH) |
No |
TLV (ACGIH) |
1 mg/m3 |
STEL (ACGIH) |
3 mg/m3 |
PEL (OSHA) |
1 mg/m3 |
MAK |
2 mg/m3, inhalable fraction |
IDLH (NIOSH) |
1000 mg/m3 |
Excerpts from Documentation for IDLHs |
Basis for original (SCP) IDLH: According to MCA [1958], phosphoric acid does not cause any systemic effect, and the chance of pulmonary edema from mist or spray inhalation is very remote. The rat oral LD50 of 1,530 mg/kg [Biofax 1970] cited by NIOSH provides a calculated IDLH of about 10,000 mg/m3. . . . Basis for revised IDLH: The revised IDLH for phosphoric acid is 1,000 mg/m3 based on acute oral toxicity data in animals [Biofax 1970]. This may be a conservative value due to the lack of relevant acute toxicity data for workers. |
Vapor Pressure |
0.02 mm Hg |
Lethal Concentration |
LC50 (rats) > 850 mg/m3/1H |
Flammability (NFPA) |
0: will not burn |
Adverse Effects |
Toxic Pneumonitis |
Yes |
Dermatotoxin |
Skin Burns |
Links to Other NLM Databases |
Health Studies |
Human Health Effects from Hazardous Substances Data Bank: PHOSPHORIC ACID
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