Phosphoric Acid: Properties, Uses, and Health Hazards

Phosphoric Acid (H₃PO₄) is a colorless, odorless, corrosive mineral acid with widespread industrial and food applications.

Common Uses

• Food/beverage: Acidulant in colas, preservative, pH adjuster
• Agriculture: Phosphate fertilizer production
• Metal treatment: Rust removal, etching, phosphating
• Dental: Etching agent for bonding
• Cleaning: Scale/rust removers

Health Hazards

Acute Exposure

• Skin/Eyes: Corrosive burns, irritation, conjunctivitis, corneal damage
• Inhalation: Respiratory irritation, coughing, dyspnea, chemical pneumonitis
• Ingestion: GI burns, nausea, vomiting, abdominal pain, potential perforation

Chronic Exposure

• Dental enamel erosion (from acidic beverages)
• Potential bone density reduction (phosphate-calcium balance)
• Kidney stress (phosphate load)
• Respiratory sensitization

Safety Measures

• Use diluted forms for most applications
• PPE: Chemical-resistant gloves, goggles/face shield, apron, ventilation
• Eyewash/shower stations accessible
• Proper storage: Corrosive cabinet, labeled, away from bases
• Spill neutralization: Weak base (sodium bicarbonate)

Phosphoric acid is safe in regulated food concentrations but hazardous in concentrated industrial forms—handle with appropriate precautions.