A Canadian government assessment has provisionally concluded that IPDI, a diisocyanate used in the production of polyurethane, is not harmful to humans or the environment.

IPDI (isophorone diisocyanate) acts as a monomer in polyurethane production, reacting with a polyol to form urethane linkages. Additionally, it is found in paints,  coatings, adhesives, sealants and floor coverings. The EU has given it a mandatory category 1 respiratory sensitisation classification under CLP, and Germany has proposed a diisocyanates restriction under REACH.

But the Canadian draft screening assessment describes the risk of harm to human health and the environment posed by the substance as low. It concludes that the substance does not meet the criteria set out in section 64 of the Canadian Environmental Protection Act (Cepa).

The authors of the Canadian draft screening assessment identified IPDI as an ingredient in enamel hardeners for two-component automotive paints available for use by consumers. The potential for consumer exposure via such products formed the basis for the calculations of risk to human health. They calculated the risk to the environment using the ecological risk classification of organic substances (ERC), a system produced by government department Environment and Climate Change Canada.

Occupational exposure was outside the scope of the assessment.

The government has initiated a 60-day public consultation. Interested parties have until 2 May to submit comments.