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Ammonia - Toxicological Overview

Key Points

Kinetics and metabolism

  • Ammonia dissolves in moisture in the air and on tissue or mucous membranes to form ammonium hydroxide, a strong base
  • Ammonium is produced in the intestines by bacteria and is efficiently absorbed from the gastrointestinal tract
  • Dermal or ocular absorptions are considered not to contribute significantly to systemic ammonium following exposure
  • Ammonia is readily metabolised in the liver to urea or glutamine
  • Ammonia is excreted primarily in the urine as urea

Health effects of acute exposure

  • Ammonia and ammonia solutions are irritant and corrosive and may be harmful by all routes of exposure
  • Acute oral exposure rapidly results in pain, excessive salivation and burns to the mouth, throat and oesophagus
  • Acute inhalation may initially cause upper respiratory tract irritation. Substantial exposures can cause burns in the oral cavity, nasopharynx, larynx and trachea, together with airway obstruction, respiratory distress and bronchiolar and alveolar oedema
  • Ammonia or ammonia solutions are corrosive in contact with tissue, and splashes to the eye may result in serious injury

Health effects of chronic exposure

  • Effects following chronic oral exposure have not been defined in humans. Experiments in animals suggest osteoporosis, occurring secondary to chronic metabolic acidosis
  • Chronic inhalation has been associated with increased cough, phlegm, wheeze and asthma
  • Ammonia is considered not to be a human carcinogen
  • Ammonia is considered not to be a human reproductive or developmental toxicant

Decontamination and First Aid       Summary of Health Effects

Prepared by J D Pritchard
CHAPD HQ, HPA
2007
Version 2

This document will be reviewed not later than 3 years, or sooner if substantive evidence becomes available.