We read with great interest the Letter to the Editor by Newman and colleagues(1) in response to our article entitled "Industries in the United States with Airborne Beryllium Exposure and Estimates of the Number of Current Workers Potentially Exposed."(2) We commend the authors of the letter for raising a number of issues that, while clearly beyond the scope of our article, are relevant to the health of beryllium workers. At this time, we want to clarify some issues regarding our goals and methods. In the hierarchy of prevention (i.e., primary, secondary, and tertiary), primary prevention is usually considered the most desirable since it is concerned with protecting susceptible individuals from disease onset. The goal of our article was to further the cause of primary prevention of beryllium sensitization and chronic beryllium disease (CBD). Specifically, we used measurements of airborne beryllium collected by the Occupational Safety and Health Administration (OSHA) to identify industries where beryllium is present and to estimate the number of employees in the United States who are currently potentially exposed to beryllium. Our article alertsworkers and company officials to the potential for beryllium exposure and the associated risks for beryllium sensitization and CBD. The authors of the Letter to the Editor offered the criticism that the "paper underestimates the number of former workers who have been exposed to beryllium." Primary prevention is pertinent to currently exposed workers. Starting with the title of our article and throughout it, we clearly stated that wewould estimate the number of current workers rather than the number of former workers. Personnel at the Department of Energy (DOE) had provided us estimates of the number of former workers who had enrolled in medical surveillance, and we reported those estimates. Also, a month before the publication of our article, other researchers published an estimate of the number of construction workers who had ever been employed at DOE sites and had potentially been exposed to beryllium.(3) A comprehensive estimate of the number of workers from both the public and private sectors who had formerly been exposed to beryllium would complement our article, with its focus on primary prevention, by serving secondary and tertiary prevention.