A cross-sectional study of workers in the chemical industry with occupational exposure to hexamethylenetetramine

Abstract

Objectives: To assess the health effects of hexamethylenetetramine (HMT) on the airways and the skin of workers in the chemical industry. Methods: A cross-sectional study was performed with 17 employees of a HMT-producing chemical plant and 16 control subjects from the plant. In addition, we examined 4 out of 5 subjects who had left the production for medical reasons during the last 10 years. Anamnestic data, total and specific IgE to four environmental allergens, lung function and bronchial responsiveness to methacholine were assessed by standard procedures. Skin prick tests (SPT) and patch tests were performed with known sensitizing substances and HMT 100 mg/ml and 2% pet and aq. Results: A high number of exposed subjects and controls reported symptoms during the previous year (64.7% vs 68.8%), most of them were not related to work. Work-related symptoms and objective parameters did not show differences between groups. No sensitizations to HMT as assessed by SPT or patch tests were found. Among those who had left the HMT production for medical reasons, 2 former baggers showed sensitizations to HMT by patch tests. These reported eczema during exposure but lost symptoms after removal from exposure. Geometric mean HMT concentrations as assessed by personal sampling were 0.3 [95% confidence intervals (CI) 0.1; 0.9] mg/m³ in shiftleaders and 0.6 (95% CI 0.3; 1.1) mg/m³ in baggers. Conclusion: High exposures to HMT may cause allergic contact dermatitis. There was no evidence of an increased risk for occupational asthma at mean airborne HMT concentrations below 1 mg/m³.