Respiratory morbidity induced by occupational inhalation exposure to formaldehyde

The potential of formaldehyde to produce chronic respiratory tract disease remains a controversial issue. The main purpose of this study was to investigate the respiratory effects, if any, of long term occupational exposure to formaldehyde. This cross-sectional study was carried out at a local melamine-formaldehyde resin producing plant. The study population consisted of seventy exposed and 24 non-exposed (referent) employees. Using respiratory questionnaire, data on respiratory symptoms were gathered. Atmospheric concentrations of formaldehyde were measured at different contaminated areas of the plant. Similarly, the parameters of pulmonary function were measured at the beginning (preshift) and at the end (postshift) of the first working day of the week. The results showed that airborne concentrations of formaldehyde exceeded current permissible levels. Additionally, significant decrements in some preshift and postshift parameters of pulmonary function of exposed workers were noted. However, a relative recovery in lung functional capacity observed following temporary cessation of exposure (preshift values). Furthermore, exposed workers had higher prevalence rates of regular cough, wheezing, phlegm, shortness of breath, chest tightness and episodes of chest illness associated with cold. The findings of this study collectively indicate that exposure to formaldehyde may induce respiratory symptoms, acute partially reversible and chronic irreversible functional impairments of the lungs.