Occupational exposure to 1,6-hexamethylene diisocyanate-based polyisocyanates in the state of Oregon, 1980-1990

Monitoring of exposure to 1,6-hexamethylene (HDI) monomers and HDI polyisocyanates in Oregon was initiated in 1980 and covered primarily spray painting and related activities. A total of 562 air samples were collected from 60 workplaces during the years 1980-1990 and analyzed for HDI and HDI polyisocyanate content. Of the total, only a small fraction (6%) of the samples exceeded the state of Oregon permissible exposure limit (PEL) of 0.02 ppm for HDI monomer; however, a much higher number (42%) of the samples exceeded the Oregon PEL of 1 mg/m3 for HDI polyisocyanates. Spray finishing operations were divided into three categories: continuous industrial spraying, auto body repair shops, and intermittent spray operations of large objects. The highest exposures among all three categories for both HDI and HDI polyisocyanates were measured during spray finishing. The geometric mean for HDI in the industrial spray operations was 0.001 ppm and for HDI polyisocyanates was 3.78 mg/m3. Frequently, the peak exposures exceeded the Oregon PEL for polyisocyanates, reaching as high as 12.2 mg/m3. In auto body shops, the mean for HDI was 0.002 ppm and for HDI polyisocyanates was 1.60 mg/m3 with peak concentrations of 0.049 ppm for HDI and 18.4 mg/m3 for HDI polyisocyanates. In the third category of spray finishing of large objects, the geometric means for three subcategories ranged from 0.001 to 0.017 ppm for HDI with a peak concentration of 0.069 ppm. The geometric means for HDI polyisocyanates ranged from 2.09 to 15.9 mg/m3 with a peak of 29.5 mg/m3. In all the surveys, the ventilation facilities and personal protective equipment were evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)