Proposal of a new risk assessment method for the handling of powders and nanomaterials.

A new approach to assess the risks inherent in the implementation of powders, including nanomaterials, has been developed, based on the OHB (Occupational Hazard Band) method which is widely spread in the chemical industry. Hazard classification has not been modified; only the control of exposure has been worked at. The method applies essentially to the prevention of the exposures to airborne materials, whatever their particle size. The method considers exposure based on seven parameters which take into account the characteristics of the materials used, their emission potential, the conditions of use, as well as classic parameters of exposure characterization like duration and frequency. The method is a pragmatic exploitation of the state-of-art and of available data, bearing in mind that a lot of them are not easily accessible to factory operators. The result of the reflection is then positioned on a hazard versus exposure matrix from which 4 levels of priority of action are defined, as in the classical OHB method used to manage pure chemical risk. This approach fills a gap in terms of risk assessment and avoids jeopardizing all that has been set up for years, while introducing new elements of decision making accessible to all operators.