We examined the prevalence of beryllium sensitization in relation to work process and beryllium exposure measurements in a beryllia ceramics plant that had operated since 1980. We interviewed 136 employees (97.8% of the workforce), ascertained beryllium sensitization with the beryllium lymphocyte proliferation blood test, and reviewed historical industrial hygiene measurements. Of eight beryllium‐sensitized employees (5.9%), six (4.4% of participating employees) had granulomatous disease on transbronchial lung biopsy. Machinists had a sensitization rate of 14.3% compared to a rate of 1.2% among other employees. Machining had significantly higher general area and breathing zone measurements than did other processes in the time period in which most beryllium‐sensitized cases had started machining work. Daily weighted average (DWA) estimates of exposure for machining processes also exceeded estimates for other work processes in that time period, with a median DWA of 0.9 μ/m³. Machining process DWAs accounted for the majority of DWAs exceeding the 2.0 μg/m³ OSHA standard, with 8.1% of machining DWAs above the standard. We conclude that lowering machining process‐related exposures may be important to lowering risk of beryllium disease. © 1996 Wiley‐Liss, Inc.