Decline in lung function after exposure to fumes from military small arms

Background: Norwegian Armed Forces received reports of acute respiratory symptoms after exposure to fumes from firing small arms HK416 using lead free ammunition. The aim of this study was to examine lung function before and after exposure to fumes from HK416 in an experimental setting using three different types of ammunition. Methods: Fifty-five healthy, non-smoking males (age 19-62 years) were randomized to three groups using one of three types of ammunition (SS109 (leaded), NM229 and NM255 (lead free)). Tests of lung function included spirometry and DLCO. The tests were performed less than 14 days before (T 0 ), shortly after (T 1 ) and 24 hours after (T 2 ) shooting. A tent was used for achieving control of the exposure. Exposure was monitored by measuring CO and regulated to keep the level between 200 and 300 ppm Results: FVC, DLCO, NO show the same trend as for FEV1. There are no significant differences (one way Anova) between the different types of ammunition concerning FEV1, FVC, DLCO, NO. Conclusions: All groups show a decline in FEV1 shortly after shooting. 24 hours after exposure FEV1 are still significantly reduced compared to the pretest values (T0). Other lung function tests show the same trend as for FEV1. We believe this is caused by an inflammatory process of the airways.