similar exposure groups that perform the tasks or jobs in the same manner and therefore are expected to have similar exposures. Monitoring can be performed on the different similar-exposure groups so that acceptability can be judged. The AIHA Exposure Assessment Strategy requires personal exposures to generally be less than 10% of the PEL (or other standard being used) for a judgment of acceptability. The strategy potentially results in lower estimated exposures of workers (Bullock and Ignacio 2006).

ADDITIONAL CONSIDERATIONS

Creation of the OSHA lead standard for general industry in the late 1970s was an important advance over occupational exposure limits that already existed. The OSHA standard is complex and includes more than the setting of a PEL or an action level. For example, air monitoring will not adequately capture lead exposures that occur via noninhalation routes, which can be important in firing ranges. In particular, ingestion of lead is of concern because of deposition of lead aerosols on hands during shooting or secondary hand contamination after contact with surfaces on which lead aerosols have collected or settled.

There are no data that directly link hand or surface contamination levels with specific BLLs, but studies have demonstrated that improved hygiene practices for both employees and the environment can lead to decreasing BLLs. Scott et al. (2012) found that although ventilation is an important method for controlling lead exposures, housekeeping can also have a substantial effect on lead contamination on surfaces in and around a shooting range. Even in ranges that have good ventilation and that use ammunition with lead-free primers, poor housekeeping or failing to decontaminate the range thoroughly before switching primers may adversely affect lead exposures. The Navy Environmental Health Center notes in its Indoor Firing Ranges Industrial Hygiene Technical Guide (NEHC 2002) that although there are no established limits for surface contamination in workplaces, OSHA (1993) has indicated in a compliance instruction for the construction industry (CPL 2-2.58) that an acceptable lead loading for nonlead work areas should be 200 μg/ft2. Appendix D of the Navy technical guide suggests clearance standards of 200 μg/ft2 for interior floors and horizontal surfaces and 800 μg/ft2 for exterior concrete (the latter is derived from an interim recommendation from the US Department of Housing and Urban Development).

It has been shown that high BLLs can result from lead ingestion during smoking and eating with lead-contaminated hands. Sato and Yano (2006) found that BLLs were substantially higher in battery-recycling employees whose hands showed lead contamination. In a longitudinal study of lead-battery employees in Taiwan, Chuang et al. (1999) found that smoking at work more than 3 days per week increased BLLs by 3.08 μg/dL compared with BLLs in those who had never smoked at work (p < 0.05). Although this is not statistically significant, mean BLLs were 1.32 μg/dL higher in employees who ate at work compared



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