“A Class Approach to Hazard Assessment of Organohalogen Flame Retardants”

A new report from the National Academies of Sciences, Engineering, and Medicine offers guidance to the Consumer Product Safety Commission (CPSC) on how to conduct a hazard assessment of nonpolymeric, additive organohalogen flame retardants (OFRs), which are used in some consumer products.

OFRs cannot be treated as a single class for hazard assessment, the report says, but they can be divided into subclasses based on chemical structure, physical and chemical properties, and predicted biologic activity. The report identifies 14 subclasses that CPSC can use to conduct a class-based hazard assessment of OFRs. Such an approach is likely to be more efficient and less costly than the traditional approach of evaluating each chemical individually, the report notes.

There is mounting evidence that many flame retardants are associated with adverse human health effects, and some flame retardants have been banned, restricted, or voluntarily phased out of use. A coalition of organizations and individuals petitioned CPSC to initiate regulatory action to ban use of OFRs in four product categories: infant, toddler, or children’s products; upholstered furniture; mattresses; and plastic electronic casings. The petitioners argued that the entire chemical class is toxic and poses a risk to consumers.

CPSC voted to grant the petition, but in order to decide whether a ban should be enacted, the agency must first conduct a hazard assessment to determine whether a chemical is toxic. CPSC asked the National Academies for guidance on how to conduct the hazard assessment for OFRs as a chemical class.

The National Academies study committee first conducted an analysis to determine whether OFRs can be treated as a single class. This involved identifying known OFRs and other structurally related organohalogen compounds. The committee found that OFRs cannot be distinguished as a single class from these other chemically similar analogues. In addition, OFRs do not have a common chemical structure or predicted biologic activity and therefore cannot be treated as a single class.

However, an approach that uses subclasses to assess the chemicals is scientifically justifiable, the committee determined.  The report outlines a process for assessing the toxicity of the 14 identified subclasses and identifies four scenarios that might occur, depending on how much data is available for the chemicals in a subclass. The report also uses two subclasses to illustrate how the proposed approach to the hazard assessment would work.

A multidisciplinary group will be needed to execute the hazard assessment, the report says. Needed expertise includes cheminformatics, computational chemistry, computational toxicology, traditional and modern toxicology, epidemiology, and risk assessment. Furthermore, integrating the evidence at various steps will require expert judgment, and policy decisions involving value judgments – for example, about what health endpoints to investigate and how much uncertainty is acceptable – will be needed to complete the assessment.

The study — undertaken by the Committee to Develop a Scoping Plan to Assess the Hazards of Organohalogen Flame Retardants — was sponsored by the Consumer Product Safety Commission. The National Academies are private, nonprofit institutions that provide independent, objective analysis and advice to the nation to solve complex problems and inform public policy decisions related to science, technology, and medicine. They operate under an 1863 congressional charter to the National Academy of Sciences, signed by President Lincoln. For more information, visit nationalacademies.org.

Visit the original press release here