Using Existing Science and Toxicology in Chemicals Policy

Historically, the policies governing the manufacture, use and disposal of synthetic chemicals have been seriously constrained by the lack of information on the hazards that chemicals may pose to human health and the environment. The paucity of chemical hazard data has also limited the validity and utility of traditional risk assessment methods, which currently rely on modeling and the application of uncertainty factors where contemporary and credible data is unavailable. New chemicals policies—such as REACH in the European Union and the laws emerging from the California EPA Green Chemistry Initiative—aim to close this data gap and enable more effective chemical assessments by requiring chemical manufacturers to generate and disclose information on their products’ hazards. Implementation of these policies, however, will involve identifying and prioritizing chemicals of concern. By necessity, this will require developing mechanisms for screening a backlog of compounds that are on the market but whose hazard traits are poorly understood.  Regulatory agencies will have to determine what body of toxicity information—if made available—would enable efficient identification of hazardous chemicals and their safer alternatives. To pilot an approach to this task, we investigated methods for establishing a toxicity testing schematic that could be used to determine if a chemical increases the risk of breast cancer. We convened an expert panel to: 1. Identify key physiological mechanisms and susceptibility factors associated with an elevated risk of breast cancer; 2. Develop a recommended set of toxicity tests, based on currently-available methods for detecting chemical contributors to breast cancer; and 3. Recommend means for addressing current gaps in toxicological methods and scientific knowledge, particularly in identifying developmental toxicants likely to contribute to a woman’s lifetime risk of breast cancer. This approach could inform the development of effective regulation of chemical hazards and improve breast cancer prevention efforts.