Pulmonary damage after modest exposure to zinc chloride smoke.

Thirteen soldiers (11 men and two women) were exposed to zinc chloride smoke (ZCS) during a combat exercise. Even though their initial symptoms were modest, a prolonged follow up with lung function testing and blood samples was undertaken due to previous cases with fatal outcome after exposure to ZCS. Four weeks after exposure there were statistically significant declines from baseline values in lung diffusion capacity and total lung capacity of 16.2% and 4.3%, respectively. At the same time plasma levels of fibrinogen and zinc were significantly elevated, though mainly within the normal range. All variables showed a tendency towards normalization at follow up 8 weeks and 6 months after exposure. These findings indicate an unexpected quantifiable damage to lung parenchyma with a remarkable delay after modest exposure to zinc chloride smoke despite sparse initial symptoms. Exposure to high concentrations of ZCS may induce adult respiratory distress syndrome (ARDS) after a symptom free period of up to 12 days from exposure. Even though none of the soldiers in the present study developed ARDS the assessment of lung diffusion capacity and acute phase reactants is proposed as a supplement when monitoring patients after exposure to ZCS.