Phosphoric acid
Synonyms & Trade Names
Orthophosphoric acid, Phosphoric acid (aqueous), White phosphoric acidPhysical Description
Thick, colorless, odorless, crystalline solid. [Note: Often used in an aqueous solution.]Molecular Weight
98.0Boiling Point
415°FMelting Point
108°FSolubility
MiscibleVapor Pressure
0.03 mmHgIonization Potential
?Specific Gravity
(77°F): 1.87 (pure) 1.33 (50% solution)Flash Point
NAUpper Exposive Limit
NALower Explosive Limit
NAIncompatibilities & 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 contactSymptoms
irritation eyes, skin, upper respiratory system; eye, skin, burns; dermatitisTarget Organs
Eyes, skin, respiratory systemPersonal 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
- Page last reviewed:April 11, 2016
- Page last updated:April 11, 2016
- Content source:
- National Institute for Occupational Safety and Health (NIOSH) Education and Information Division