OSHA Puts the Squeeze on Asthma-Causing Polyurethanes

Isocyanates are a key ingredient in spray-foam and polyiso insulation as well as “green” wood products.

Too many workers in construction and related industries are at risk for potentially fatal asthma associated with production of polyurethane compounds, says the U.S. Occupational Safety and Health Administration (OSHA). The agency recently announced a National Emphasis Program aimed at reducing or eliminating health effects from occupational exposure to isocyanates, a key component of products like foam insulation. The plan will pair education with increased enforcement.

Isocyanates are ubiquitous in the building industry. When combined with a polyol, they react to form the polyurethanes found in high-performance insulation products, foam furniture cushions, coatings, and no-added-formaldehyde wood products made with MDI (methyl diphenyl diisocyanate). Although not considered dangerous after curing, isocyanates emitted during the curing process are a leading cause of occupational asthma and chemical sensitivity.

The respiratory effects of isocyanates have been known since the 1950s, according to OSHA—and many chemicals in this group are also “potential human carcinogens or known to cause cancer in animals”—but recommendations for reducing exposure are sometimes ignored. Industries targeted for more inspections due to a history of overexposure include:

• building and construction (see “EPA Takes Action on Spray-Foam Health Risks”)

• paint manufacturing

• plastic foam manufacturing (see “Can We Replace Foam Insulation?”)

• furniture manufacturing (due to wood binders, adhesives, and lacquers as well as foam cushions)

• textile manufacturing (due to nonwoven fabrics, such as polyurethane upholstery)

Recommended measures to decrease isocyanate exposure include site isolation, ventilation, and protective clothing.