By Lynn L. Bergeson and Carla N. Hutton
 
The U.S. Environmental Protection Agency (EPA) announced on July 21, 2022, that the meeting minutes and final report (final report) are now available for the April 19-21, 2022, Science Advisory Committee on Chemicals (SACC) virtual meeting regarding EPA’s proposed Draft Systematic Review Protocol Supporting TSCA Risk Evaluations for Chemical Substances Version 1.0 (Draft Protocol). As reported in our December 21, 2021, memorandum, EPA released the Draft Protocol for public comment on December 20, 2021. 86 Fed. Reg. 71891. According to EPA’s December 20, 2021, press release, the Draft Protocol will strengthen EPA’s approach to reviewing and selecting the scientific studies that are used to inform Toxic Substances Control Act (TSCA) chemical risk evaluations and ensure that EPA has the best tools under TSCA to protect human health and the environment. EPA intends to issue its response to the SACC’s recommendations along with any revisions to the approach in 2023.

Charge Question 1: TSCA Systematic Review Protocol Document (Chapters 1-7)

The final report states that the SACC raised some substantive comments that require edits or explanation from EPA. According to the SACC, the Draft Protocol “is closer to a framework to carry out systematic review and other evaluation processes for TSCA risk evaluation.” Multiple SACC members recommended specifying systematic review and non-systematic review processes (e.g., risk assessment) within the Draft Protocol. To increase transparency, the Draft Protocol needs to: (1) start with the problem formulation; (2) describe how Populations, Exposures, Comparators, and Outcomes (PECO) or Receptors, Exposure, Setting or Scenario, and Outcomes (RESO) statements are developed and refined through the process; (3) describe the process of systematic review, evidence synthesis, and integration; and (4) clearly link the steps of the systematic review back to the larger risk evaluation process.

Charge Question 2: Strategies for Literature Search and Screening (Chapter 4)

According to the final report, overall, the SACC found the methods for searching and screening well described in Chapter 4. The general process for searching the peer-reviewed literature was considered robust, but the SACC noted concerns that methods for searching gray literature were neither robust nor complete. The method for searching gray literature does not currently find relevant information from states, non-governmental organizations (NGO), or community groups. The SACC recommends EPA identify authoritative reviews from government agencies and begin with these as a starting point to make more efficient use of time and resources.

Charge Question 3: Method to Assess the Quality of Evidence (Chapter 5)

The final report states that in general, the SACC noted that the Draft Protocol is an improved approach compared with the 2018 method. There was greater transparency and clarity in the data evaluation methods, as EPA’s process for evaluating the data across various evidence streams was well described and explained. The SACC made several recommendations to include more detail regarding the role of certain evidence types, such as biochemical and cellular-level outcomes, and to describe how supplemental data sources will be reviewed, evaluated, and incorporated into the systematic review or what criteria will be used to make the determination to consider/incorporate these data. In addition, EPA should re-evaluate the domain “accessibility” and identify whether an alternative term or phrase would be more appropriate to capture the elements under consideration. The SACC stated that EPA should be specific about the types of quality and validity issues it is considering and maintain appropriate categorizations of each instead of referring to them collectively under a blanket term.

Charge Question 4: Approaches for Integrating Evidence in Exposure and Hazard (Chapter 7)

According to the final report, SACC agreed this is a difficult and multi-faceted task and generally found that several aspects of the chapter were helpful, such as the hierarchies of data and the documentation on integration. As written, the Draft Protocol presents a complicated and potentially inefficient method for integrating data within the various disciplines, however. The final report states that many SACC members were concerned that criteria used to judge quality may exclude useful data that are not of high quality but nevertheless may have specific value for other downstream applications (e.g., corroboration of results or to assist with coherence of a data stream). In addition, the evidence integration process inappropriately introduces criteria for data selection that should be specified earlier in the process.