• Epidemiological methods
• EPIDEMIOLOGY
• ENVIRONMENTAL HEALTH
• TOXICOLOGY

Scientific, policy and consumer concerns regarding the health and environmental impacts of toxic substances have resulted in increased pressures to restrict potentially hazardous chemicals in processes and products.1 However, selecting chemical alternatives without regard to their hazard profiles can have regrettable consequences when substitutes are as toxic or are even more toxic than the chemicals they replace. Examples of regrettable substitutions include flame retardants (eg, substituting tris(1,3-dichloro-2-propyl) phosphate for polybrominated diphenyl ether), solvents (eg, substituting n-propyl bromide for methylene chloride and trichloroethylene (TCE)) and replacements for endocrine disrupting plastics components (eg, substituting bisphenol-S for bisphenol-A).2 These mistakes occur, in part, because performance and cost are elevated over health and safety in chemical selection decisions. They also occur because the environmental health community has been slow to provide strategies and guidelines for identifying, evaluating and adopting alternatives that include a thoughtful examination of environmental health and safety alongside cost and performance considerations.

When public health scientists identify problematic chemicals, scientific justification for substituting that chemical based on identifying a safer alternative is rarely pursued. In a previous JECH commentary, we noted the challenges related to an over-reliance on studying environmental problems versus solutions in environmental health science, using the example of bisphenol-A.3 We argued that the ‘problem-centred’ approach to chemicals management is often reactive, extremely resource intensive, fosters extended debates over regulatory benchmarks, and inaction that benefits neither health nor innovation. This reactive approach is fortified by a number of factors including policies that require significant evidence of risk before action can be taken, which then focuses research and agency resources on risk assessment, risk management and enforcement; the lack of interdisciplinary collaboration between those designing molecules, materials, and products and those evaluating their risks; and the fact that many chemicals of concern have important functionality and cost …