Reduction in lead exposures with lead-free ammunition in an advanced urban assault course

Abstract

The training of soldiers for urban conflict involves marksmanship instruction on outdoor flat ranges and the teaching of close-quarter battle techniques in indoor facilities, referred to as shoot houses, where intense firing exercises can generate high air lead levels from small arms ammunition, flash bang grenades, and explosive devices. Levels of lead and copper in air were evaluated during five training activities of a 45-day training course using both stationary general area and breathing zone sampling over a 2-year period. Individual blood lead values were determined prior to and at course completion. Mean breathing zone lead concentrations for the five training activities ranged from 0.014 on the outdoor flat range to 0.064 mg/m³ inside shoot houses; with a change to lead-free ammunition the values were reduced to a range of 0.006–0.022 mg/m³. Isolated flash bang grenades generated very high general area lead concentrations (2.0 mg/m³), which in training were associated with the highest measured breathing zone concentration (0.16 mg/m³). For copper, mean breathing zone concentrations increased from 0.010 to 0.037 mg/m³ with the change to lead-free frangible ammunition on the outdoor range, but remained below the permissible exposure limit for copper fume. Inside shoot houses, mean breathing zone copper concentrations exceeded the permissible exposure limit with ball and lead-free frangible ammunition, ranging from 0.077–0.13 mg/m³. With the introduction of lead-free ammunition, when comparing the blood lead differences between start and finish of the course, there was a significant reduction in the mean blood lead difference from 13.3 µg/dL to 5.4 µg/dL. Options for mitigation of potentially high exposure areas using improved ventilation designs are discussed. These results advocate for improved designs for shoot house training facilities, stress the importance of removing lead from ammunition and explosive devices for training, and promote the continued need for implementation of controls to mitigate and manage metal exposures during training.

Keywords:

• Blood lead
• copper
• frangible ammunition
• lead
• shoot house

Acknowledgments

We wish to acknowledge and thank Army Soldier and Civilian instructors and active-duty students, and the leadership of the 1st Special Warfare Training Group, U.S. Army John F. Kennedy Special Warfare Center and School who participated in and supported this project. Leadership of Company D, 2^nd Battalion, 1st Special Warfare Training Group, U.S. Army John F. Kennedy Special Warfare Center and School provided access to and support for completing this project. We wish to also acknowledge many current and former staff members of the Industrial Hygiene Field Services Division and the Laboratory Sciences Directorate of the Army Public Health Center who contributed to sample collection, analysis, and data compilation. This work was supported by the U.S. Army Public Health Center.

Disclaimer

The views are those of the author(s) and do not necessarily reflect the official policy of the Department of Defense, Department of the Army, U.S. Army Medical Department or the U.S. Army Public Health Center.