Phosphoric acid

Synonyms & Trade Names

Orthophosphoric acid, Phosphoric acid (aqueous), White phosphoric acid

CAS No.

7664-38-2

RTECS No.

TB6300000

DOT ID & Guide

1805 154(liquid or solution)
3453 154(solid)

Formula

H₃PO₄

Conversion

IDLH

1000 mg/m³
See: 7664382

Exposure Limits

NIOSH REL

TWA 1 mg/m³ ST 3 mg/m³

OSHA PEL

TWA 1 mg/m³ See Appendix G

Measurement Methods

NIOSH 7903;
OSHA ID165SG
See: NMAM or OSHA Methods

Physical Description

Thick, colorless, odorless, crystalline solid. [Note: Often used in an aqueous solution.]

Molecular Weight

98.0

Boiling Point

415°F

Melting Point

108°F

Solubility

Miscible

Vapor Pressure

0.03 mmHg

Ionization Potential

Specific Gravity

(77°F): 1.87 (pure) 1.33 (50% solution)

Flash Point

Upper Explosive Limit

Lower Explosive Limit

Noncombustible Solid

Incompatibilities & Reactivities

Strong caustics, most metals [Note: Readily reacts with metals to form flammable hydrogen gas. DO NOT MIX WITH SOLUTIONS CONTAINING BLEACH OR AMMONIA.]

Exposure Routes

inhalation, ingestion, skin and/or eye contact

Symptoms

irritation eyes, skin, upper respiratory system; eye, skin, burns; dermatitis

Target Organs

Eyes, skin, respiratory system

Personal Protection/Sanitation

(See protection codes)
Skin:Prevent skin contact
Eyes:Prevent eye contact
Wash skin:When contaminated
Remove:When wet or contaminated
Change:Daily
Provide:Eyewash (>1.6%), Quick drench (>1.6%)

First Aid

(See procedures)
Eye:Irrigate immediately
Skin:Water flush immediately
Breathing:Respiratory support
Swallow:Medical attention immediately

Respirator Recommendations

NIOSH/OSHA

Up to 25 mg/m³:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode*

Up to 50 mg/m³:

(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter.
Click here for information on selection of N, R, or P filters.

(APF = 50) Any self-contained breathing apparatus with a full facepiece
(APF = 50) Any supplied-air respirator with a full facepiece

Up to 1000 mg/m³:
(APF = 2000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode

Emergency or planned entry into unknown concentrations or IDLH conditions:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus

Escape:

(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter.
Click here for information on selection of N, R, or P filters.

Any appropriate escape-type, self-contained breathing apparatus

Important additional information about respirator selection

Phosphoric acid

NIOSH REL

OSHA PEL

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