Monitoring of low level arsenic exposure during maintenance of ion implanters

To delineate potential exposure in ion implanter maintenance, the authors recruited 21 maintenance engineers (exposed group) and 10 computer programmers (controls) at three semiconductor manufacturing facilities. Samples of air, wipes, and urine; used cleaning cloths; and used gloves were collected for the characterization of arsenic exposure. Arsenic levels were very low in environmental samples, but high arsenic levels were found in some wipe samples, used cleaning cloths, and gloves. The average baseline content of urinary arsenic measured for maintenance engineers was 3.6 microg/g creatinine. Maintenance engineers experienced an increase of 1.0-7.8 microg/g creatinine in urinary arsenic levels during ion implanter maintenance. Results of a mixed-model analysis indicated that urinary arsenic levels were associated significantly with time series (p = .0001), and the extent of association was different among the three facilities (p = .0226). The results of this study indicate that arsenic intake via ingestion, rather than through inhalation, might play a significant role in the elevation of urinary arsenic levels. However, a series of urine samples with self-reference continue to be a good approach for the monitoring of low-level arsenic exposure.