June 28, 2017
On June 22, 2017, EPA released final rules providing frameworks for selecting and evaluating substances under the Toxic Substances Control Act (TSCA). These rules were required by the Lautenberg Chemical Safety for the 21st Century Act (LCSA), enacted on June 22, 2016 to update TSCA. This email is part of a one-week series focusing on aspects of the most recent rulemaking release.
The Prioritization of Chemicals rule describes the process whereby EPA identifies candidate substances from among the TSCA inventory of existing chemicals and designates them as either High or Low Priority for subsequent risk evaluation. Several changes from January’s proposed rule are evident in this final version. First, in response to public comments, EPA has deleted the proposed pre-prioritization provisions, choosing not to finalize the pre-prioritization process at this time. Instead, EPA plans to re-open the public comment period in Fall, 2017, to consider additional input on how this process should be implemented, including consideration for public participation. In the meantime, EPA will continue to use select candidates for prioritization from previous activities, such as those identified during the updates to the TSCA work plan from 2014.
The designation process remains similar to the proposed rule from January. The rule stipulates that EPA must designate all nominated chemicals as either High Priority or Low Priority based on hazard and exposure potential. EPA is tasked with considering all possible uses of a given chemical in its prioritization process (known as its “conditions of use,” or the circumstances under which a chemical is manufactured, processed, distributed in commerce, used, or disposed of). A notable change in the final rule, however, is that EPA indicates that it will identify the specific condition(s) of use that were the basis for the High- or Low-Priority designation. Risk evaluation begins as soon as High Priority designations are finalized.
The Risk Evaluation rule describes the process whereby EPA evaluates potential risks from the use of a particular chemical, and whether this chemical has an “unreasonable risk” of injury to human health or the environment under the conditions of use. The new rule includes expanded discussions and definitions for several critical concepts in EPA’s risk evaluation process, including weight of evidence and unreasonable risk. EPA has also added direct references to methodologies it will consider when conducting its reviews (e.g., the Institute of Medicine standards for systematic review). As in the prioritization step, TSCA requires EPA to evaluate all conditions of use for each chemical, and consequently, the potential for exposure to the population from all uses.
In response to public comments regarding the potential difficulties of tasking EPA with identifying and regulating conditions of use within the statutory timeframe, the new rule indicates that the Agency has the discretion to determine the conditions of use that it will address in its risk evaluation. The focus will be on the conditions of use that raise the greatest potential for risk, while still allowing for a timely and scientifically credible evaluation of the chemical substance. Note also that EPA has added language regarding “legacy uses,” noting that they are not excluded from the definition of conditions of use. Thus, it is possible that EPA will consider risk from the sum of background exposures from legacy uses and current uses of the chemical. Finally, while the proposed rule allowed EPA to designate a specific chemical use as high risk before completing a full risk evaluation of all uses, EPA indicated that in the new rule, it may also designate some uses as low risk before it has fully evaluated all potential uses.
Please contact us if you have questions about how the prioritization and risk evaluation rules may affect your business. For the remainder of the week, Gradient will provide additional alerts on EPA’s TSCA-related rulemaking and document releases, and will highlight opportunities for stakeholder involvement.
About Gradient
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.
Jiaru Zhang, M.P.H., Senior Toxicologist
jzhang@gradientcorp.com
Heather N. Lynch, M.P.H., Senior Toxicologist
hlynch@gradientcorp.com
Lisa A. Bailey, Ph.D., Senior Toxicologist
lbailey@gradientcorp.com
Lorenz R. Rhomberg, Ph.D., ATS, Principal
lrhomberg@gradientcorp.com
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