Overexposures to Lead at a Covered Outdoor Firing Range

Significant overexposures to airborne lead were found in a covered, outdoor firing range among seven cadets during firing of conventional, nonjacketed, lead bullets. The mean lead concentrations in general area air samples and personal-breathing-zone air samples were 68.36 μg/m3 and 128.46 μg/m3, respectively, calculated as an 8h, time-weighted average (TWA). Eight (44%) of 18 area air samples, taken as far as 50 yards from the firing line, and 10 (67%) of 15 personal breathing zone air samples exceeded the current Occupational Safety and Health Administration (OSHA) standard for occupational exposure to airborne lead (50μg/m3). Blood lead levels (using a t-test) were found to increase significantly in all cadets after day 2 (p < 0.0001) and day 5 (p < 0.0007) of firing conventional, nonjacketed, lead bullets. None of the blood level values exceeded the OSHA standard of 40 μg/dl. A strong positive correlation (r = 0.92; p < 0.000001) existed between personal-breathing-zone air lead levels and the number of rounds fired by the cadets. A positive correlation also existed between blood lead levels and cumulative personal breathing zone air lead levels (r = 0.85; p < 0.02), as well as the total number of rounds fired (r = 0.84; p < 0.02). Based on environmental and medical data, it was concluded that a potential health hazard may exist due to inorganic lead exposure to cadets at this covered outdoor range during firing exercises.