Isocyanates are in the hardener of many autobody paints. They react readily with other chemicals to form polyurethane, which makes the finish on cars hard, durable and resistant to weather and UV light. There are many different types of isocyanates, for example HDI, at right,
Spraying paint has the highest exposure, by far. Near spraying on the shop floor is next highest, barely visible on this graph.
Isocyanates are found in the air of body shops.
We have measured isocyanates in the air during routine tasks in body shops. The graph, above right, shows which tasks had higher exposures to isocyanates,
Spraying clearcoat usually has the highest exposure, followed by sealer and primer. Basecoat usually does not contain hardener or isocyanates.
Many surfaces in a body shop are contaminated with isocyanates, from the ones that come in contact with paints to door handles and surfaces in the office.
Isocyanates on body shop surfaces
We also measured the amount of isocyanate contamination on surfaces in body shops. We used wipe sampling for these tests. The graph below shows the percentage of tests that were positive for isocyanate on various surfaces (all surfaces were tested at least 13 different times).
Mixing and spraying paint can get isocyanates on workers' skin, but so can sanding paint!
Isocyanates on autobody workers’ skin
We also wipe tested the skin of workers after doing various auto repair tasks in the shop. The graph below shows which tasks had the most positive isocyanate samples.