Prevention is, of course, the key to controlling beryllium-induced disease, but it is not easy. The current permissible exposure limit for beryllium, which has been in effect since 1949, is 2 μg/m3 as an 8-h time-weighted average. In addition, a ceiling limit of 5 μg/m3, not to be exceeded for > 30 min, and a maximum peak limit of 25 μg/m3, never to be exceeded, have been established. This level of exposure, however, does not protect those who are susceptible to sensitization from becoming sensitized. As a result, a considerable effort is currently underway to identify new standards. It is also important to recognize that beryllium has been categorized by the International Agency for Research on Cancer15 as a human carcinogen.