Acute exposure If hydrogen<unk>  is inhaled it can cause a coma with seizures, apnea, and cardiac arrest, with death following in a matter of seconds. At lower doses, loss of consciousness may be preceded by general weakness, dizziness, headaches, vertigo, confusion, and perceived difficulty in breathing. At the first stages of unconsciousness, breathing is often sufficient or even rapid, although the state of the person progresses towards a deep coma, sometimes accompanied by pulmonary edema, and finally cardiac arrest. A cherry red skin color that changes to dark may be present as the result of increased venous hemoglobin oxygen saturation. Despite the similar name,<unk>  does not directly cause cyanosis. A fatal dose for humans can be as low as 1.5 mg/kg body weight. Other sources claim a lethal dose is 1–3 mg per kg body weight for vertebrates. Chronic exposure Exposure to lower levels of<unk>  over a long period (e.g., after use of improperly processed cassava roots, which are a primary food source in tropical Africa) results in increased blood<unk>  levels, which can result in weakness and a variety of symptoms, including permanent paralysis, nervous lesions, hypothyroidism, and miscarriages. Other effects include mild liver and kidney damage.
Cyanide poisoning
Foreign body aspiration
Chlorine gas poisoning
Carbon monoxide poisoning
Salicylate poisoning
Nitrogen dioxide poisoning
Strychnine poisoning
Tin poisoning