Hydrogen cyanide is highly toxic by all routes of exposure and may cause abrupt onset of profound CNS, cardiovascular, and respiratory effects, leading to death within minutes. Exposure to lower concentrations of hydrogen cyanide may produce eye irritation, headache, confusion, nausea, and vomiting followed in some cases by coma and death.
Explanation:
Drinking 0.5–1 mg/L of hydrogen cyanide can result in symptoms that are mild, 1–2 mg/L moderate, 2–3 mg/L severe, and greater than 3 mg/L generally result in death.
