Effects of formaldehyde on the mucous membranes and lungs. A study of an industrial population.

One hundred nine workers and 254 control subjects were studied to evaluate the effects of formaldehyde on the mucous membranes and lungs. A modified, respiratory symptom questionnaire and spirometry were administered to all study participants before and after their work shift, and formaldehyde levels were determined for each test subject. Over the course of the monitored work shift, test subjects demonstrated a dose-dependent excess of irritant symptoms and a statistically significant decline in certain lung function parameters. Analysis of test and control subject data combined revealed a correlation between formaldehyde exposure and these pulmonary changes. Baseline spirometry values were not significantly different between test and control groups, and formaldehyde-exposed workers did not report an excess of respiratory symptoms. Formaldehyde is a dose-dependent irritant of the eyes and mucous membranes at low-level exposures. It can exert a small, across-shift effect on airways but after a mean exposure of ten years does not appear to cause permanent respiratory impairment.