in the respiratory tract. Recent research indicates that surface area and dissolution rate in the lungs also contribute to the rate of release of beryllium ions.
The epidemiologic literature suggests that developing BeS or CBD is process-related (see Chapter 3). It is not possible, however, to conclude confidently from those studies that specific types of beryllium are more toxic than others. Further epidemiologic study might be able to answer that question, but epidemiology is often a blunt analytic tool. Detecting differences in beryllium toxicity as a function of particle characteristics requires exposure of large numbers of people to various types of beryllium for an appropriate duration to be at risk for developing disease. Such cohorts have not yet been identified. Until there is strong evidence that some forms of beryllium are more or less toxic than others, it is prudent from a safety and health perspective to treat them equally.
More research is needed on the aerosol characteristics of detectable beryllium, including particle size distribution, surface area, and chemical composition.
Research is also needed to understand the extent of skin exposure to beryllium and the associated risks, if any. The effectiveness of personal protection equipment and other workplace controls to reduce skin exposure should be investigated.