Exposure limit values for nanomaterials--capacity and willingness of users to apply a precautionary approach.

In the European Union, the legal obligation for employers to provide a safe workplace for processing manufactured nanomaterials is a challenge when there is a lack of hazard information. The attitude of key stakeholders in industry, trade unions, branch and employers' organizations, and government policy advisors toward nano reference values (NRVs) has been investigated in a pilot study that was initiated by a coalition of Dutch employers' organizations and Dutch trade unions. NRVs are developed as provisional substitutes for health-based occupational exposure limits or derived no-effect levels and are based on a precautionary approach. NRVs have been introduced as a voluntary risk management instrument for airborne nanomaterials at the workplace. A measurement strategy to deal with simultaneously emitting process-generated nanoparticles was developed, allowing employers to use the NRVs for risk assessment. The motivational posture of most companies involved in the pilot study appears to be pro-active regarding worker protection and acquiescent to NRVs. An important driver to use NRVs seems to be a temporary certainty employers experience with regard to their legal obligation to take preventive action. Many interviewees welcome the voluntary character of NRVs, though trade unions and a few companies advocate a more binding status.