June 13, 2018
On May 31, 2018, EPA released problem formulation documents for the first ten chemical risk evaluations required under the Lautenberg Chemical Safety for the 21st Century Act (LCSA) amendments to the Toxic Substances Control Act (TSCA). These set out the populations, exposures, and toxic effects that the Agency will examine in forthcoming risk evaluations for these chemicals. In response to public input on the scoping documents and further research by EPA, the problem formulation documents refine the conditions of use, initial conceptual models, and analysis plans provided in earlier “scoping documents” published in June 2017. EPA will be accepting public comments on the documents through July 26th (Federal Register notice). While EPA does not intend to revise the problem formulation documents, the comments and information it receives will inform the development of the subsequent draft risk evaluations.
Although EPA did not add any condition of use, several conditions of use that appeared in the earlier scoping documents were removed during the problem formulation. For example, legacy uses of asbestos (i.e, adhesives and sealants, roof and non-roof coatings, building materials other than cement) and consumer uses of trichloroethylene (TCE) in paints and coating were removed from the evaluations. One notable change that affects more than half of the chemicals is that general population exposures (via chemical waste releases to air, water, and soil are no longer included. EPA’s rationale is that these exposures undergo regulatory evaluation by existing programs. Several industrial and consumer exposure pathways have also been removed. For example, consumer exposure via waste handling was removed for several chemicals (e.g., TCE, tetrachloroethylene [PCE], and carbon tetrachloride) because EPA anticipates that products containing these chemicals will be disposed of in original containers, such as aerosol cans. For most chemicals, some remaining exposure pathways will not be further analyzed, mostly based on expected low risks identified during the problem formulation. EPA will be doing no further analysis on any exposure pathway or scenario for one chemical, pigment violet.
The preambles to each problem formulation document explain how EPA intends to limit the consideration of certain uses and exposure pathways, particularly those covered by regulatory programs other than TSCA. Each chemical’s plan spells out the specific alternative regulatory coverage that the agency proposes to apply for consideration of exposures through ambient air, water, and disposal. This stance has created some controversy, including questions as to whether such limits are consistent with the LCSA mandates, and the fate of these proposals will be watched closely.
The problem formulation documents indicate that EPA is planning to conduct a full hazard evaluation for many of the chemicals, including consideration of data from alternative test methods (e.g, high-throughput screening methods; read-across; in vitro studies). EPA will also consider existing hazard and risk data, such as the Integrated Risk Information System (IRIS) and other chemical-specific risk assessments. For several chemicals (e.g., TCE, PCE, and carbon tetrachloride), EPA indicates that worker exposures are regulated by the Occupational Safety and Health Administration’s (OSHA’s) permissible exposure limits (PELs), but it is not yet clear how the PELs will be considered in the occupational risk evaluations.
EPA is implementing systematic review approaches to identify, select, assess, integrate, and summarize the findings of studies supporting the risk evaluations. Inclusion/exclusion criteria for systematic review of the June 2017 literature search results for each chemical are included in the problem formulation document appendices.
Please contact us if you have any questions about how the problem formulation documents may affect EPA’s risk evaluation process for your chemicals.
Lisa A. Bailey, Ph.D.
| Heather N. Lynch, M.P.H.
| Lorenz R. Rhomberg, Ph.D., ATS
Gradient is an environmental and risk sciences consulting firm renowned for our specialties in Toxicology, Epidemiology, Risk Assessment, Product Safety, Contaminant Fate and Transport, Industrial Hygiene, Geographic Information Systems, and Environmental/Forensic Chemistry. We employ sound science to assist national and global clients in resolving their complex problems relating to chemicals in the environment, in the workplace, and in consumer products.