Hydrogen selenide

A deadly poison by inhalation. Very poisonous irritant to skin, eyes, and mucous membranes. Causes central nervous system effects in humans. An allergen. Can cause damage to the lungs and liver as well as conjunctivitis. It has been found that repeated exposures to concentrations of 0.3 ppm prove fatal to experimental animals by causing a pneumonitis, as well as injury to the liver and spleen. Causes garlic odor of breath, dizziness, nausea. Concentrations of 0.3 ppm are readily detected by odor, but there is no noticeable irritant effect at that level. Concentrations of 1.5 ppm or higher are strongly irritating to the eyes and nasal passages.As in the case of hydrogen sulfide, the odor of hydrogen selenide in concentrations below 1 ppm disappears rapidly because of olfactory fatigue. The odor and irritating effects do not offer a dependable warning to workers who may be exposed to gradually increasing amounts and therefore become used to it. Due to its extreme toxicity and irritating effects, it seldom is allowed to reach a concentration in which it is flammable in air. Very little data are available on possible chronic effects of this material, but it is logical to assume that when the concentration of this gas is low enough to avoid the irritant effects, only the systemic effects will be noticeable.Dangerous fire hazard when exposed to heat or flame; will react vigorously with powerful oxidizing agents, such as H2O2, HNO3. Dangerous; forms explosive mixtures with air; keep away from heat and open flame. See also SELENIUM COMPOUNDS and HYDRIDES.