EXPOSURES AND HEALTH-EFFECTS - AN EVALUATION OF WORKERS AT A SODIUM-AZIDE PRODUCTION PLANT

Sodium azide is the principal gas-generating agent used to inflate aut omobile supplemental restraint systems, more commonly called airbags. Although sodium azide is known to affect the cardiovascular system by causing peripheral vasodilation, there is no published literature desc ribing occupational exposures to sodium azide in the rapidly growing a utomobile airbag industry. In 1994-1995, the National Institute for Oc cupational Safety and Health (NIOSH) conducted a cross-sectional study of health complaints reported by sodium azide production workers at t he only continuous sodium azide production facility in the United Stat es. The NIOSH evaluation consisted of a plant industrial hygiene surve y, a symptom questionnaire, ambulatory blood pressure monitoring, and blood azide analysis. Personal breathing zone air monitoring revealed exposures to sodium azide and hydrazoic acid (a reactant product) at l evels greater than the NIOSH Recommended Exposure Limits (RELs). In so me cases, exposures exceeded the REL despite the use of air-supplied r espirators. The questionnaire revealed that most workers reported head ache (10 of 11 [91%]), episodes of low blood pressure (9 of 11 [82%]), and palpitations (8 of 11 [73%]) occurring in the production areas wi thin the 6 months preceding the study. Mild headache (4 of 11 [36%]) w as the only symptom reported during our 24-hr medical survey. Ambulato ry blood pressure monitoring revealed one asymptomatic employee with a drop in blood pressure (defined as a drop in systolic [at least 20 mm Hg] and diastolic [at least 10 mm Hg] blood pressure) during a period of exposure to sodium azide at a level five times the NIOSH REL. Impr ovements in plant engineering controls, increased attention to employe e hygiene practices, and a more comprehensive respiratory protection p rogram were recommendations made by NIOSH to reduce exposures at the p lant. All facilities handling sodium azide should be aware of the pote ntial toxicity of sodium azide and hydrazoic acid. (C) 1996 Wiley-Liss , Inc.