Beryllium and its compounds are highly toxic substances. Beryllium enters the body almost entirely by inhalation, but the toxic reaction is body-wide rather than in the lung alone, in much the same way that lead may enter the body by inhalation and cause systemic disease. Experimental evidence suggests that little beryllium is absorbed through the intestinal wall. Traumatic introduction of beryllium and its compounds subcutaneously can give rise to local damage, but beryllium does not enter the body through the unbroken skin. Beryllium intoxication can cause bronchitis, pnemonitis, dermatitis, acute pneumonitis, chronic pulmonary granulomatosis etc.
This is an intoxication arising from the inhalation of any beryllium compound (beryl excepted). The precise quality and quantity of the disease-producing dose is at present unknown, although there is some knowledge of both certainly harmful and probably safe dose levels gained from a registry of case records established in 1952 in the USA.
In 1999, the US president ordered a comprehensive review of studies of nuclear power plant workers' health, after the Energy Department concluded that some of the workers at plants that had supplied beryllium to the government for bomb-making had developed beryllium disease, an incurable lung ailment.