Methylene diphenyl diisocyanate (MDI): EU classification; impact of REACH; worker and consumer exposure - perception versus facts

Methylene diphenyl diisocyanate (MDI) is being used increasingly as an alternative resin in the composite wood industry for environmental, indoor air, production capacity or quality reasons. This paper gives an overview of the hazards, classification, regulations and exposure risks related to the use of MDI and MDI bonded wood products. Its aim is to provide factual scientific information to address some of the concerns regularly encountered when introducing MDI as a resin. Like all chemicals, MDI has its hazards and is regulated within existing regulatory frameworks like Globally Harmonized System (GHS) the European Regulation for the REACH, Evaluation, Authorization and Restriction of Chemicals (REACH) and Classification, Labelling & Packaging (CLP). It is important to understand the risks associated with chemicals in the workplace to raise awareness with workers. Understanding safety issues has equal value in identifying where to implement risk reduction measures so workers are protected, and in ensuring investments are economically feasible. The inhalation exposure risks of MDI are given based on an extensive dataset and compared with other agents present in the workplace, i.e. wood dust and formaldehyde. In addition, this paper addresses the risk for consumers for the use of MDI bonded composite wood products (CWPs). The conclusion is that MDI has been classified as a hazardous chemical; however, safe use can be demonstrated within the REACH framework. The exposure risks of MDI, compared to other chemical agents present in the workplace, are significantly lower and can be reduced further if actions are taken to control wood dust. Furthermore, there is no need for concern regarding exposure to consumers if MDI bonded CWPs are used in buildings or homes.