Food & Drink / Compounds / Diammonium phosphate

Diammonium phosphate in food: ingestion safety

Low risk

(People-specific data is limited; this page draws from human adult context.) Diammonium phosphate (DAP, 18-46-0) is the most widely used phosphorus fertilizer globally. Low acute toxicity: oral LD50 rat ~2840 mg/kg. GRAS as food-grade ingredient (pH adjuster, leavening). Primary hazard is respiratory and eye irritation from dust inhalation during handling. Chronic health concern is limited; phosphate and ammonium are normal metabolites.

What is diammonium phosphate?

Also known as: DAP, Ammonium hydrogen phosphate, (NH4)2HPO4, Diammonium hydrogen orthophosphate.

CAS number
7783-28-0
Molecular formula
H9N2O4P
Molecular weight
132.06 g/mol
SMILES
[NH4+].[NH4+].OP(=O)([O-])[O-]
PubChem CID
24540

Risk for people

Low risk

Diammonium phosphate (DAP, 18-46-0) is the most widely used phosphorus fertilizer globally. Low acute toxicity: oral LD50 rat ~2840 mg/kg. GRAS as food-grade ingredient (pH adjuster, leavening). Primary hazard is respiratory and eye irritation from dust inhalation during handling. Chronic health concern is limited; phosphate and ammonium are normal metabolites.

Regulatory consensus

1 regulatory bodyhas classified Diammonium phosphate.

AgencyYearClassificationNotes
FDA1975GRAS — Generally Recognized as Safe (food-grade applications)

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where you encounter diammonium phosphate

  • Agriculture
  • Food
  • Fire Retardant

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Diammonium phosphate:

  • Triple superphosphate (TSP)
    Trade-offs: No nitrogen component. Similar P content. Does not volatilize ammonia.
    Relative cost: Similar
  • Rock phosphate
    Trade-offs: Very slow P release; only effective in acidic soils. Approved for organic farming.
    Relative cost: Similar to DAP

Frequently asked questions

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Sources (1)
  1. ECHA Registration Dossier — Diammonium phosphate — reference

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →