Abstract: A male worker, 26 years old, was reported coma with ammonia inhalation due to explosion of a liquid ammonia steel canister. The chest X-ray images revealed scattered patchy shadows in both lungs. The significantly higher levels of lactate dehydrogenase(1 193 U/L), creatine kinase(1 408 U/L), and creatine kinase isoenzyme CK-MB(62 U/L)indicated toxic myocardial damage. After treated with mechanical ventilation and lung lavage by bronchoscopy, the patient was recovered and discharged. No further symptom or sign was found in the follow-up visit. It is imperative that employers and employees should take appropriate measures to prevent ammonia intoxication in good time and receive promptly treatment to prevent myocardial damage.