Consumer Safety and Diisocyanates

Unreacted Diisocyanates in Spray Polyurethane Foam and
Action from California’s Department of Toxic Substances Control (DTSC)

In March 2014, the California Department of Toxic Substances Control (DTSC) listed Spray Polyurethane Foam (SPF) Systems containing “unreacted” or “wet” diisocyanates as a test case for its new Safer Consumer Products Regulation. Diisocyanates are well-studied and regulatory limits exist for MDI, a diisocyanate, used in SPF.

The business of chemistry touches more than 96 percent of the products that we all use every day and accounts for thousands of new products and innovations each year. For example, the products of diisocyanates (DII) chemistry—from impact-absorbing vehicle parts, to bike helmets, to insulation used in refrigerators to preserve food—contribute to the safety of modern conveniences.

The chemical industry makes the safety and responsible use of its products a priority. While certain parts of America’s chemical management system require modernization, a robust system of laws and industry initiatives oversees the development and use of chemical products, enhances scientific understanding and makes safety information available to the public.

Policies to Promote Innovation and Safety

Americans must feel confident that the federal regulatory system is keeping pace with the applications of chemistry, including the use of diisocyanates. Our nation’s primary chemicals management law must be updated to keep pace with scientific advancements while the agencies work to determine that chemical products are safe for their intended use—while also encouraging innovation and protecting American jobs. Learn more about policies that can help American chemistry continue innovatingcreating jobs and enhancing safety.

To learn more about chemical safety, including the more than a dozen federal laws that create a safety net to oversee the safe use of chemical products, visit the Consumer SafetyProduct Safety and Workplace Safety pages on the ACC Website.

How Are Consumers Protected from Potential Exposures to Diisocyanates?

The vast majority of diisocyanates manufactured are for industrial use. Overall, consumer exposures to unreacted diisocyanates are expected to be of very low magnitude and frequency. The U.S. Environmental Protection Agency (EPA) notes that “polyurethane products, such as mattresses, pillows, and bowling balls, are considered completely cured products before they are sold.” EPA also states that “[c]ompletely cured products are fully reacted and therefore are considered to be inert and non-toxic.” Diisocyanates are known to cause respiratory sensitization at concentrations above allowable workplace limits; however, exposure to such air concentrations are highly unlikely to occur in consumer products. Consumer products containing uncured diisocyanates (e.g. certain adhesives and glues) generally are accompanied by product safety information like warning labels, including the characteristics of the chemicals, their approximate cure time and how to properly protect yourself while handling the product.

How Does "Curing" Take Place During Formation of a Polyurethane Product?

This can be explained by looking at how diisocyanates are among the building blocks used to make polyurethanes (PU) products. Curing refers to the reaction that occurs between the two primary chemicals used to form a PU product. These primary chemicals are commonly referred to as a diisocyanate (A-side material) and a polyol (B-side material). The A-side material, or diisocyanate, is highly reactive and curing begins immediately upon mixing with the B-side material. The cure time varies depending on the type of polyurethane product being produced, the ingredient formulations and other factors in the manufacturing process.

Many PU products are completely cured and therefore considered “inert” before they are sold, such as mattresses, pillows, furniture cushions, car seating, refrigerator insulation, footwear, ski bindings or inline skates. This means that the original reactive ingredients, the diisocyanates and the polyols, in the fully cured polyurethane product are no longer present in their original form. As a result of the reaction, they were transformed during production into the finished polyurethane product.

For more answers to questions about diisocyanates, visit the Frequently Asked Questions section.