The Cardiff Atomic Weapons Establishment (AWE) plant, located in Cardiff, Wales, United Kingdom, used metallic beryllium in their beryllium facility during the years of operation 1961-1997. The beryllium production processes included melting and casting, powder production, pressing, machining, and heat and surface treatments. As part of Cardiff's industrial hygiene program, extensive area measurements and personal lapel measurements of airborne beryllium concentrations were collected for Cardiff workers over the 36-year period of operation. In addition to extensive air monitoring, the beryllium control program also utilized surface contamination controls, building design, engineering controls, worker controls, material controls, and medical surveillance. The electronic database includes 367,757 area sampling records at 101 locations and 217,681 personal lapel sampling records collected from 194 employees over the period 1981-1997. Similar workplace samples were collected from 1961 to 1980, but they were not analyzed because they were not available electronically.Annual personal mean sampling concentrations for all workers ranged from 0.11 to 0.72 micrograms per cubic meter (μg/m[sup 3]) with 95th percentiles ranging from 0.22 to 1.89 μg/m[sup 3]; foundry workers worked in the highest concentration areas with a mean of 0.87 μg/m[sup 3] and a 95th percentile of 2.9 μg/m[sup 3]. Area sampling concentrations, as expected, were lower than personal sampling concentrations. Mean annual area sample concentrations for all locations ranged from 0.02 to 0.32 μg/m[sup 3]. The area sample 95th percentile concentrations for all years were below 0.5 μg/m[sup 3]. For the overwhelming majority of samples, airborne beryllium concentrations were below the 2.0 μg/m[sup 3] standard. Although blood lymphocyte testing for beryllium sensitization has not been routinely conducted among these workers, this metal beryllium processing facility is the only large scale beryllium facility of its kind to have experienced only one unique a case of clinical chronic beryllium disease (CBD) ascertained by traditional medical monitoring procedures. The treating physician determined that this lung disease was likely caused by a systems reaction resulting from a mound contaminated with beryllium. However,he could not rule out the potential for inhalation exposure. Over the 17 years of measurement data analyzed, on occasion, airborne beryllium concentrations have exceeded 2.0 μg/m[sup 3]; however, the Cardiff experience demonstrates that strict and consistent adherence to exposure control measures that emphasized airborne and surface levels and appropriate engineering controls, work practices, and use of personal protective equipment appears to have successfully prevented the incidence of clinical CBD with the exception of one unique case. [ABSTRACT FROM AUTHOR]