Is a reduction in residual volume a sub-clinical manifestation of hydrogen sulfide intoxication?

BACKGROUND: A number of employees at an aircraft factory were accidentally exposed to hydrogen sulfide. Because of concern that this may have resulted in lung injury, forty-seven workers were referred for clinical and physiological evaluation. METHODS: Comprehensive pulmonary function tests were performed including spirometry, flow volume curves, static lung volumes, and diffusion capacity for carbon monoxide. RESULTS: The results obtained indicated that ten people (23%) had an isolated reduction in residual volume. This was an unexpected finding as other physiological indices of lung function were within normal limits. Clinical examination was also normal, therefore, radiological investigations were considered inappropriate. CONCLUSIONS: It is suggested that the decrement in residual volume, in the presence of other normal indices of lung function, could represent a sub-acute manifestation of hydrogen sulfide intoxication.