Regulatory Developments

EPA Proposes Procedures to Prioritize Chemicals for Risk Evaluation under TSCA

January 18, 2017

The U.S. Environmental Protection Agency (EPA) proposed on January 17, 2017, procedures to establish the risk-based screening process and criteria that EPA will use to identify chemical substances under the Toxic Substances Control Act (TSCA) as either High-Priority Substances for risk evaluation, or Low-Priority Substances for which risk evaluations are not warranted at the time. 82 Fed. Reg. 4825. The proposed rule describes the processes for identifying potential candidates for prioritization, selecting a candidate, screening that candidate against certain criteria, formally initiating the prioritization process, providing opportunities for public comment, and proposing and preparing final priority designations. EPA notes that prioritization is the initial step in a new process of existing chemical substance review and risk management activity established under recent amendments to TSCA. EPA incorporated all of the elements required by new TSCA, but also supplemented those requirements with additional criteria it expects to consider, some clarifications intended to provide greater transparency, and additional procedural steps to ensure effective implementation. EPA requests comments on all aspects of the proposed rule. Comments are due March 20, 2017.

Prioritization Overview

Based on new TSCA Sections 6(b)(1) through (3), EPA proposes to include four steps or phases in prioritization: (1) pre-prioritization; (2) initiation; (3) proposed designation; and (4) final designation. During the pre-prioritization phase, EPA proposes to apply the statutory preferences in new TSCA Section 6(b)(2), along with other criteria, to narrow the pool of potential candidates and identify a single chemical substance (or category of chemical substances) to screen against the statutory criteria in new TSCA Section 6(b)(1)(A). Aside from the statutory preferences, EPA states that new TSCA does not otherwise direct or limit EPA in how to select a chemical substance on which to initiate prioritization, requiring only that the process be “risk-based.” At the initiation step, EPA will announce a candidate chemical substance and give the public a 90-day comment period to submit relevant information. At the proposed designation step, EPA will propose to designate a chemical substance as either a High-Priority Substance or a Low-Priority Substance, publish the proposed designation and the information, analysis, and basis used to make the designation, and take public comment a second time for 90 days. At the final designation step, EPA will either issue a final High-Priority Substance designation and initiate a risk evaluation, or issue a final Low-Priority Substance designation, in which case it will not conduct a risk evaluation on the chemical substance unless and until information leads EPA to revisit that priority designation.

Policy Objective

EPA states that the prioritization process under new TSCA is the “principal gateway to risk evaluation” as EPA makes a judgment as to whether a particular chemical substance warrants further assessment. The key objective, according to EPA, should be to guide EPA towards identifying the High-Priority Substances that have the greatest hazard and exposure potential first. EPA notes that it may also consider the relative hazard and exposure of a potential candidate’s likely substitute(s) to avoid moving the market to a chemical substance of equal or greater risks. EPA states that the prioritization process is not intended to be an exact scoring or ranking exercise, however, and EPA is not proposing such a system in this rule. According to EPA, the level of analysis necessary to support an exact ranking system is not appropriate at the prioritization stage, where the sole outcome is a decision on whether EPA will further evaluate the chemical substance. Instead, EPA “intends to conserve its resources and the Agency’s deeper analytic efforts for the actual risk evaluation.”

According to EPA, Low-Priority Substance designations serve some of the same policy objectives. Although new TSCA does not require EPA to designate more than twenty Low-Priority Substances, EPA states that doing so ensures that chemical substances with “clearly” low hazard and exposure potential are taken out of consideration for further assessment, “thereby conserving resources for the chemical substances with the greatest potential risks.” Identifying Low-Priority Substances as part of this process also gives the public notice of chemical substances for which potential risks are likely low or nonexistent, and provides industry some insight into which chemical substances are likely not to be regulated under TSCA.

Scope of Designations

Under the proposed prioritization process, EPA would designate the priority of a “chemical substance” as a whole, and would not limit the designation to a specific use or subset of uses. EPA states that it proposes this approach in response to “clear statutory directives”: the relevant provisions of TSCA Section 6 repeatedly refer both to the designation and evaluation of “chemical substances” under the “conditions of use.” “Conditions of use” are broadly defined as “the circumstances, as determined by the Administrator, under which a chemical substance is intended, known, or reasonably foreseen to be manufactured, processed, distributed in commerce, used, or disposed of.”

According to EPA, although some commenters at the August 10, 2016, public meeting suggested that the prioritization process should allow EPA to designate a specific use of a chemical substance as a High-Priority Substance or a Low-Priority Substance, EPA states that it does not interpret the statute to support such an interpretation. To the contrary, the addition of the phrase “conditions of use” was intended to move EPA away from its past practice of assessing only narrow uses of a chemical substance, towards a comprehensive approach to chemical substance management. While EPA states that it “clearly” retains some discretion in determining those conditions of use, as a matter of law, EPA “considers that it would be an abuse of that discretion to simply disregard known, intended, or reasonably foreseen uses in its analyses.”


New TSCA Section 6(b)(1)(C) requires that the prioritization process last between nine and 12 months. EPA proposes that initiation of the prioritization process begin upon publication of a notice in the Federal Register identifying a chemical substance for prioritization and providing the results of the screening review. The process would be complete upon publication of a notice in the Federal Register announcing a final priority designation nine to 12 months later. According to EPA, the timeframe serves dual purposes: the minimum nine-month timeframe ensures that stakeholders have “ample” notice of upcoming federal action on a given chemical substance, and opportunity to engage with EPA early in the process. EPA states that the 12-month maximum timeframe, coupled with the default-to-high provision discussed below, “keeps the existing chemical substances review pipeline in a forward motion, and prevents EPA from getting mired in analysis before ever reaching the risk evaluation step.” Be that as it may, we note that the 12-month deadline is expressly tied to the use of Section 4(a)(B)(2) authority for prioritization testing. For reasons that are not clear, EPA never discusses this provision’s connection to the prioritization process.

Categories of Chemical Substances

TSCA Section 26 provides EPA with the authority to take action on categories of chemical substances. EPA notes that the proposed rule most often references “chemical substances,” and proposes to include a clear statement in the regulation that nothing in the proposed rule shall be construed as a limitation on EPA’s authority to take action with respect to categories of chemical substances, and that, where appropriate, EPA can prioritize and evaluate categories of chemical substances. We note that the inclusion of categories in this process is expressly allowed in Section 6(b)(1)(A).

Chemicals Subject to Prioritization

Generally, all chemical substances listed on the TSCA Inventory are subject to prioritization. EPA states that new TSCA contemplates that all chemical substances on the TSCA Inventory will eventually be prioritized into either High- or Low-Priority Substances, and that all High-Priority Substances will be evaluated. Chemical substances newly added to the TSCA Inventory following EPA’s completion of pre-manufacture review under TSCA Section 5 are also candidates for prioritization. EPA notes that such chemical substances “are not likely to be High-Priority candidates in light of the risk-related determination” that EPA must make pursuant to TSCA Section 5(a)(3), however.

TSCA further requires EPA to go through a separate process of determining which chemical substances on the TSCA Inventory are still actively being manufactured. As reported in our January 17, 2017, memorandum, “TSCA: EPA Proposes Requirements for TSCA Inventory Notification (Active-Inactive),” EPA has initiated a separate rulemaking for that purpose. This distinction will inform EPA’s exposure judgments during the prioritization process. EPA states that there is nothing in TSCA that prohibits it from initiating the prioritization process on an “inactive” chemical substance, however, and ultimately designating that chemical substance as either a High-Priority Substances (e.g., if exposures of concern arise from ongoing uses) or a Low-Priority Substance. We hope that this is a general statement by EPA and not an indication that EPA would contemplate meeting the requirement for 20 low-priority designations by selecting chemicals from the inactive list.

Pre-prioritization Considerations

As discussed above, new TSCA requires EPA to establish a process for designating a chemical substance as either a High-Priority Substance or a Low-Priority Substance. New TSCA includes a “preference” for chemical substances on the 2014 Update to the TSCA Work Plan, but otherwise leaves EPA with broad discretion to choose which chemical substance to put into that process. The proposed rule includes a discussion of what EPA call the “criteria” it expects to use to cull through the chemical substances on the TSCA Inventory. These include “criteria” that EPA will use to identify potential candidates for High-Priority Substances or Low-Priority Substances, and that describe how the extent of available information on potential candidates will affect whether they are selected for prioritization. By our reading, what EPA calls “criteria” are best thought of as “considerations” (in fact, this is how factors such as hazard and exposure potential, persistence and bioaccumulation, and so forth are described in Section 6(b)(1)(A)). EPA’s notable failure to discuss actual criteria and their role in the prioritization process is a regrettable omission in the proposed rule. Perhaps it is EPA’s intent to retain the flexibility to apply the criteria used in the Work Plan process without ever discussing and taking comment on the actual Work Plan criteria in the proposed prioritization rule.

According to EPA, in identifying potential candidates for High-Priority Substance designations, EPA proposes to seek to identify chemical substances where available information suggests that the chemical substance may present a hazard and that exposure is present under “one or more conditions of use,” but where an “unreasonable risk” determination cannot be made without a more extensive or complete assessment in a risk evaluation. EPA states that it interprets the statutory definition of a High-Priority Substance (“may present an unreasonable risk [. . .] because of a potential hazard and a potential route of exposure”) to set a fairly low bar, and EPA expects that a large number of chemical substances will meet this definition. EPA may then prioritize a “chemical substance” as a whole, basing its identification of a potential candidate as a High-Priority Substance, and ultimately the proposed designation, on a single condition of use, provided the hazard and exposure associated with that single use support such a designation. EPA states this proposal is based on the statutory definition of a High-Priority Substance, “which is clear that the standard for the chemical as a whole can be met based on a single condition of use (‘because of a potential hazard and a potential route of exposure’).”

Conversely, in identifying potential candidates for Low-Priority Substance designation, EPA proposes to seek to identify chemical substances where the information indicates that hazard and exposure potential for ‘“all conditions of use’ are so low that EPA can confidently set that chemical substance aside without doing further evaluation.” EPA states that by comparison, new TSCA’s definition of a Low-Priority Substance (‘“based on sufficient information, such substance does not meet the standard for [. . .] a high-priority substance’) is fairly rigorous, and effectively requires EPA to determine that under no condition of use does the chemical meet the High-Priority Substance standard.” Consequently, EPA expects it will be more difficult to support such designations. While not determinative, EPA states that it believes that its Safer Chemicals Ingredients List (SCIL) “will be a good starting point for identifying potential candidates for Low-Priority Substance designations.”

In the preceding two paragraphs, we note with concern that EPA never makes clear what the role of “risk” is in making prioritization determinations which require a Section 6(b)(1)(B)(i) conclusion of “may present an unreasonable risk.” For example, is EPA suggesting that a chemical, having low health concerns and moderate environmental toxicity but no environmental releases or exposures based on its conditions of use, could nonetheless be a candidate for a High-Priority designation?

EPA proposes to include the following list of additional exposure and hazard considerations that can be used to narrow the field of potential candidates: (1) persistent, bioaccumulative, and toxic (PBT); (2) used in children’s products; (3) used in consumer products; (4) detected in human and/or ecological biomonitoring programs; (5) potentially of concern for children’s health; (6) high acute and chronic toxicity; (7) probable or known carcinogen; (8) neurotoxicity; or (9) other emerging exposure and hazard concerns to human health or the environment, as determined by EPA. EPA drew these considerations from its 2012 TSCA Work Plan methodology, which was the process EPA used to prioritize chemical substances for assessment under old TSCA. We note that the proposed rule describes these considerations as “criteria” despite the fact that the actual criteria used to, for example, identify PBT chemicals are never discussed in the proposal. EPA states that it will evaluate one or more of these nine considerations, and chemical substances that meet one or more of these criteria may be identified as potential candidates for High-Priority Substance designations. For example, according to EPA, if a chemical substance is highly toxic and used in consumer products, EPA may wish to consider that chemical substance as a potential High-Priority Substance candidate. EPA may also choose to identify potential candidates based on other criteria that suggest the chemical substance may otherwise present a human health or environmental concern, as contemplated in the “catch-all” provision (9). EPA notes that the fact that a chemical substance meets one of these criteria “is not determinative of an outcome, including whether or not EPA will select the chemical substance to go into the prioritization process and/or the priority designation that the chemical substance will ultimately receive.” Conversely, chemical substances that meet none of these criteria may be good potential candidates for Low-Priority Substance designation. EPA states that the considerations are intended to serve as a general guide, based on EPA’s current understanding of “important considerations” regarding potential chemical risk. EPA states that while it drew the considerations from its 2012 Work Plan methodology, it will apply them differently for prioritization. In the TSCA Work Plan context, only chemicals meeting these initial criteria were eligible for listing on Work Plan. For purposes of prioritization under TSCA, “the considerations do not determine eligibility, but rather are designed to help EPA to narrow its focus.”

When prioritizing metals or metal compounds, EPA notes that it must use the 2007 Framework for Metals Risk Assessment (Framework) (or a successor document addressing appropriate considerations for conducting a risk assessment on a metal or metal compound that is peer reviewed by the Science Advisory Board). During the prioritization process, however, EPA will not be conducting chemical “risk assessments” and therefore, EPA states, much of the Framework will not be directly relevant. EPA makes this statement despite the explicit reference to use of the Framework in “identifying priorities” and the fact that prioritization involves a risk-based screening process. EPA interprets this statutory requirement to ensure that its analysis and considerations during the prioritization process take into account the special attributes and behaviors of metals and metal compounds that are relevant to judgments of risk. For example, according to EPA, this might include consideration of the Framework’s Key Principles that differentiate inorganic metals and metal compounds from organic and organometallic compounds, and their unique attributes, properties, issues, and processes. Because EPA will not conduct risk assessments on metals or metal compounds for purposes of prioritization, the proposed rule does not refer to sections that provide guidance on how to incorporate the Key Principles into risk assessments. As a general matter, EPA’s discussion strikes us an attempt to downplay the role of the Framework in the prioritization process and to allow EPA to forestall consideration of its provisions until the risk evaluation stage.

Information Availability

EPA notes that a key consideration in the pre-prioritization phase is the existence and availability of risk-related information on a candidate or potential candidate chemical substance. Because EPA has only 12 months to complete the prioritization process, immediately initiate a risk evaluation for High-Priority Substance, and complete the risk evaluation within three years of initiation, EPA cannot assume that it will be able to require the generation of critical information during these time frames. Furthermore, new TSCA does not grant EPA the discretion to delay either of these processes significantly, pending development of information. Consequently, prior to initiating the prioritization process for a chemical substance, EPA will generally review the available hazard and exposure-related information, and evaluate whether that information would be sufficient to allow EPA to complete both the prioritization and risk evaluation processes. As part of its evaluation, EPA expects to consider the quality, objectivity, utility, and integrity of the available information. To the extent the information is not currently available or is insufficient, EPA will determine whether information can be developed and collected, reviewed, and incorporated into analyses and decisions in a timely manner. EPA states that the proposed rule “makes it clear that sufficiency of available information is likely to be a crucial factor in the selection of the chemical substances that EPA chooses to put into the prioritization process.”

EPA stresses that if it identifies information gaps during the prioritization or risk evaluation processes, it could be difficult to require the development of necessary information, and receive, evaluate, and incorporate that information into analyses and decisions within the statutory timeframes. Tests necessary for risk evaluation could take months or years to develop and execute, plus additional time would be required for EPA to issue the order or rule, and to collect, review and incorporate the new information. To avoid such a scenario, EPA states that it will need to do a “significant amount” of upfront data gathering and review. This approach will allow EPA to stay on track to meet relevant statutory deadlines -- “particularly those for risk evaluation.”

According to EPA, the proposed rule makes clear that it generally expects to use this new authority, as appropriate and necessary, to gather the requisite information prior to initiating prioritization. This could include TSCA information collection, testing, and subpoena authorities, including those under TSCA Sections 4, 8, and 11(c), to develop needed information. Given the importance of ensuring that sufficient information is available to conduct the prioritization and risk evaluation processes, EPA proposes to include this consideration during the earliest stage in the process, when identifying potential candidates. This criterion remains relevant even after EPA has selected a candidate and screened that chemical substance against the statutory criteria in TSCA Section 6(b)(1)(A), however. If at any time prior to the publication of a notice in the Federal Register initiating prioritization, EPA determines that more information will be necessary to support a prioritization designation or a subsequent risk evaluation, EPA notes that it can choose not to initiate prioritization for that chemical substance pending development of additional information.

We note with some amazement that, in its discussion in this unit, EPA neglects to discuss TSCA Section 4(a)(2)(B) and its clear role in and relevance to informing the prioritization process.

Selection and Screening of a Candidate Chemical Substance

New TSCA requires that EPA give preference to chemical substances listed in the 2014 update of the TSCA Work Plan for Chemical Assessments that: (1) have a persistence and bioaccumulation Score of three; and (2) are known human carcinogens and have high acute and chronic toxicity. New TSCA Section 6(b)(2)(B) further requires that 50 percent of all ongoing risk evaluations be drawn from the 2014 Update to the TSCA Work Plan for Chemical Assessments, meaning that EPA must draw at least 50 percent of High-Priority Substance candidates from the same list. By operation of the statute, new TSCA requires that all TSCA Work Plan chemical substances eventually be prioritized. EPA notes that it is premature to presume that those chemical substances will necessarily be prioritized as High-Priority Substances, or that EPA would find unreasonable risk, however.

Aside from these statutory preferences, new TSCA does not limit how EPA must ultimately select a candidate chemical substance for prioritization. EPA proposes that it will select a candidate -- for either a High-Priority Substance or a Low-Priority Substance -- based on the policy objectives, prioritization considerations, and information availability described above. According to EPA, the development of the proposed rule, including these policy objectives, considerations, and criteria, was informed by its experience implementing the 2012 TSCA Work Plan methodology, which has been EPA’s primary tool for identifying candidate chemical substances for further assessment under TSCA. In addition, EPA states that it “fully recognizes the important role that stakeholders can play” in helping it identify candidates for prioritization or to understand better the unique uses or characteristics of a particular chemical. EPA “continues to welcome this type of engagement and dialogue early in the process, including during the pre-prioritization phase.” While the proposed rule provides multiple opportunities for public feedback during the prioritization process, EPA requests comment on whether and how it should solicit additional input at the pre-prioritization phase. Given EPA’s objective to avoid simply moving the market to substitute chemical substances of equal or greater risks, EPA also requests comment on whether and how it should take into account information on the availability of chemical substitutes during this phase of the prioritization process.

Once EPA selects a single candidate chemical substance or category of chemical substances, EPA will screen the selected candidate against the “specific criteria and considerations” in new TSCA Section 6(b)(1)(A). As we have noted, these are best thought of as considerations and not “criteria”; actual criteria for these considerations are never discussed. The Section 6(b)(1)(A) considerations include: (1) the chemical substance’s hazard and exposure potential; (2) the chemical substance’s persistence and bioaccumulation; (3) potentially exposed or susceptible subpopulations; (4) storage of the chemical substance near significant sources of drinking water; (5) the chemical substance’s conditions of use or significant changes in conditions of use; and (6) the chemical substance’s production volume or significant changes in production volume. Because new TSCA does not prohibit EPA from expanding the statutory screening criteria, EPA further proposes the additional criterion: (7) any other risk-based criteria relevant to the designation of the chemical substance’s priority, in EPA’s discretion. EPA states that this final “criterion allows the screening review to adapt with future changes in our understanding of science and chemical risks.” In addition, according to the proposed rule, EPA “fully recognizes the important role that stakeholders can play in helping the Agency to identify candidates for prioritization or to better understand the unique uses or characteristics of a particular chemical. EPA continues to welcome this type of engagement and dialogue early in the process, including during the pre-prioritization phase.” While the proposed rule provides multiple opportunities for public feedback during the prioritization process, EPA requests comment on whether and how it should solicit additional input at the pre-prioritization phase.

EPA notes that the screening review is not a risk evaluation, but rather a review of available information on the chemical substance that relates to the screening criteria. We observe that even here, EPA does not describe the review as involving a “risk-based screening process.” EPA states that it expects to evaluate all relevant sources of information while conducting the screening review, including, as appropriate, the hazard and exposure sources listed in Appendices A and B of the 2012 TSCA Work Plan methodology. Ultimately, the screening review and other considerations during the pre-prioritization phase are meant to inform EPA’s decisions on: (1) whether to initiate the prioritization process on a particular chemical substance; and (2) once initiated, the proposed designation of that chemical substance as either a High-Priority Substance or as a Low-Priority Substance.

Initiation of Prioritization

For purposes of triggering the nine to twelve month statutory timeframe, the prioritization process officially begins when EPA publishes a notice in the Federal Register identifying a chemical substance for prioritization. The proposed rule specifies that EPA will publish the results of the screening review in the Federal Register, describing the information, analysis, and basis used to conduct that review and providing in the docket copies of relevant information not otherwise protected as confidential business information (CBI) under TSCA Section 14. Publication of the notice in the Federal Register also initiates a 90-day public comment period. For each chemical substance, EPA will open a docket to facilitate receipt of public comments and access to publicly available information throughout the process. Interested persons can submit information regarding the results of the screening review or any other information relevant to the chemical substance. According to the proposed rule, of particular interest to EPA will be information related to “conditions of use” that are missing from the screening results. EPA will consider all relevant information received during this comment period. Consistent with new TSCA Section 6(b)(1)(C)(iii), the proposed rule further allows EPA to extend this initial public comment period for up to three months to receive and/or evaluate information developed from a test order, commensurate with EPA’s need for additional time to receive and/or evaluate this information. As a practical matter, EPA states that it “is unlikely to often extend this initial public comment, given EPA’s intention to ensure that all or most of the necessary information is available before initiating the prioritization process. Further, a three month window would not often provide a sufficient time to gather, let alone consider, new test data for the prioritization process.” EPA generally expects this to be the case even with the authority to collect such information more quickly under the new test order authority in new TSCA Section 4.

Proposed Priority Designation

Based on the results of the screening review, relevant information received from the public in the initial comment period, and other information as appropriate, EPA will propose to designate the chemical substance as either a High-Priority Substance or Low-Priority Substance. In making this proposed designation, as directed by new TSCA, EPA will not consider costs or other non-risk factors.

The proposed rule provides that EPA will publish the proposed designation in the Federal Register, along with an identification of the information, analysis, and basis used to support a proposed designation, in a form and manner that EPA deems appropriate, and provide a second comment period of 90 days, during which time the public may submit comments on EPA’s proposed designation. EPA proposes to use the same docket for this step of the process. According to EPA, because the supporting documentation for a proposed High-Priority Substance designation is “likely to foreshadow what will go into a scoping document for risk evaluation, EPA will be particularly interested in early comments on the accuracy of scope-related information such as the chemical’s ‘conditions of use.’”

In the event of insufficient information at the proposed designation step, EPA proposes to designate a chemical substance as a High-Priority Substance. According to the proposed rule, EPA “expects this situation to occur infrequently based on its application of the criteria and considerations during the pre-prioritization phase.” If for some reason the information available to EPA is insufficient to support a proposed designation of the chemical substance as a Low-Priority Substance, however, consistent with new TSCA, the proposed rule requires EPA to propose to designate the chemical substance as a High-Priority Substance. New TSCA requires that the prioritization process lead to one of two outcomes by the end of the 12-month deadline: a High-Priority Substance designation or a Low-Priority Substance designation. There is no third option to allow EPA either to require the development of additional information or to toll this deadline. New TSCA specifically requires that a Low-Priority Substance designation be based on “information sufficient to establish” that a chemical substance meets the definition. There is no comparable statutory requirement for High-Priority Substance designations. EPA states that it is also relevant that the effect of designating a chemical as a High-Priority Substance is that EPA further evaluates the chemical substance. By contrast, a Low-Priority Substance designation is a final EPA determination that no further evaluation is warranted -- “a determination that constitutes final agency action, subject to judicial review.”

According to EPA, the “logical implication of this statutory structure is that scientific uncertainty in this process (including as a result of insufficient information) is to weigh in favor of a High-Priority Substance designation, as it is merely an interim step that ensures that the chemical will be further evaluated.” EPA states that this “would also ensure that this process would not create any incentives for parties to withhold readily available information, or inadvertently discourage the voluntary generation of data, as could occur were EPA to establish, for example, a default designation to Low-Priority.” As a practical matter, however, EPA expects this situation to occur infrequently, based on its proposed criteria and considerations that will generally ensure that sufficient information is available to conduct a risk evaluation before initiating prioritization. Priority designations, whether based on sufficient information or a lack of sufficient information, “are neither an affirmation of risk nor safety. EPA therefore recognizes that all priority designations will need to be carefully communicated to the public.”

For proposed designations as Low-Priority Substances, EPA proposes to require that all comments that could be raised on the issues in the proposed designation be presented during the comment period. EPA will consider any issues not raised to have been waived, and such issues may not form the basis for an objection or challenge in any subsequent administrative or judicial proceeding. EPA states that this is a “well-established principle of administrative law and practice, e.g., Nuclear Energy Institute v EPA, 373 F.3d 1251, 1290-1291 (DC Cir. 2004), and the need for such a provision is reinforced by the statutory deadlines under which EPA must operate here.” EPA is restricting this to Low-Priority Substance designations, as it is the last opportunity for public input before EPA’s action becomes final, and “thus it is imperative that any issues are shared during this public comment period.” By contrast, designation of a chemical substance as a High-Priority Substance is not a final agency action. The statute mandates additional opportunities for public input during the risk evaluation process, and EPA states that it “does not consider it appropriate to restrict the public’s ability to comment during these subsequent processes based on this early phase proceeding.”

Final Priority Designation

After considering any additional information collected during the proposed designation step, as appropriate, the last step in the prioritization process is for EPA to issue a final designation of a chemical substance as either a High-Priority Substance or a Low-Priority Substance. The proposed rule specifies that EPA will publish the priority designation in the Federal Register, and will use the same docket. Again, new TSCA prohibits EPA from considering costs or other non-risk factors in this designation. And, as with the proposed designation step, if information available to EPA remains insufficient to support the final designation of the chemical substance as a Low-Priority Substance, EPA will issue the final designation as a High-Priority Substance. Although final High-Priority designations based on insufficient information are unlikely for all the reasons described above, EPA notes that such a designation would require EPA to conduct a risk evaluation on that substance, and to support the risk evaluation with adequate information. EPA would need to develop or require development of the necessary information and complete the risk evaluation within the three-year statutory deadline.

Repopulation of High-Priority Substances

New TSCA requires EPA to issue a final designation for at least one new High-Priority Substance upon completion of a risk evaluation for another chemical substance, other than a risk evaluation that was requested by a manufacturer. Because the timing for the completion of a risk evaluation and/or the prioritization process will be difficult to predict, EPA intends to satisfy this one-off-one-on replacement obligation as follows: in the notice published in the Federal Register announcing the final designation of a new High-Priority Substance, EPA will identify the complete or near-complete risk evaluation that the new High-Priority Substance will replace. So long as the designation occurs within a reasonable time before or after the completion of the risk evaluation, EPA states that this “will satisfy Congress’ intent while avoiding unnecessary delay and the logistical challenges that would be associated with more perfectly aligning a High-Priority Substance designation with the completion of a risk evaluation.”

Effect of Final Priority Designation

Final designation of a chemical substance as a High-Priority Substance requires EPA to immediately begin a risk evaluation on that chemical substance. EPA states that it is important to note that High-Priority Substance designation does not mean that EPA has determined that the chemical substance presents a risk to human health or the environment -- only that EPA intends to consider the chemical substance for further risk review and evaluation. A High-Priority Substance designation is not a final agency action and is not subject to judicial review or review under the Congressional Review Act (CRA). Final designation of a chemical substance as a Low-Priority Substance means that a risk evaluation of the chemical substance is not warranted at the time, but does not preclude EPA from later revising the designation, if warranted. Notably, EPA states, “a Low-Priority Substance designation is explicitly subject to judicial review.”

Revision of Designation

New TSCA provides that EPA may revise a final designation of a chemical substance from a Low-Priority Substance to a High-Priority Substance at any time based on information available. The proposed rule outlines the process EPA will take to revise such a designation. Specifically, EPA would: (1) re-screen the chemical substance incorporating the relevant information; (2) re-initiate the prioritization process and take public comment; (3) re-propose a priority designation and take public comment; and (4) reissue the final priority designation. EPA states that it will not revise a final designation of a chemical substance from a High-Priority Substance to a Low-Priority Substance, “but rather see the risk evaluation process through to its conclusion.”


EPA notes that a number of stakeholders have asked whether EPA should define a number of important terms in this rule (e.g., “best available science,” “weight-of-the-evidence,” “sufficiency of information,” “unreasonable risk,” and “reasonably available information”). EPA responds that many of the terms used in the proposed rule are not novel concepts and are already in use, and their meaning is discussed extensively in existing EPA guidance. For example, extensive descriptions for the phrases “best available science,” “weight-of-the-evidence,” and “sufficiency of information” can be found in EPA’s Risk Characterization Handbook and other existing EPA guidance. EPA states that it believes further defining these and other terms in the proposed rule is “unnecessary and ultimately problematic.” These terms have and will continue to evolve with changing scientific methods and innovation, and codifying specific definitions may “inhibit the flexibility and responsiveness of the Agency to quickly adapt to and implement changing science.” Instead, EPA intends to use existing guidance definitions and to update definitions and guidance as necessary. EPA specifically requests public input on this issue, stating that it welcomes public comments regarding the pros and cons of codifying these or other definitions and/or approaches for these or any other terms. EPA also encourages commenters to suggest alternative definitions that EPA should consider for codification in this procedural rule. While we appreciate the issues EPA notes, we regret that EPA did not wrestle with these concepts and outline their operation in the context of the proposed rule. For example, there are several scenarios that call for weight of evidence (WOE) including prioritization, Section 6 risk evaluations, and Section 5 determinations. The information that supports risk-based conclusions for each of these scenarios differs in quantity and quality. We believe there is value in starting from a conceptual model, deriving characteristics for WOEs for each of these varied purposes in new TSCA, and then describing those characteristics to make clear how they differ. For example, the Work Plan Chemicals Method assigns weights to different components -- this is an ingredient leading to an approach to WOE for this step. The WOEs for other scenarios (risk evaluation, new chemicals) may work differently and these differences can be described and discussed.

As noted above, we believe that EPA needed to discuss the role of Section 4(a)(2)(B) prioritization testing orders in the operation of the prioritization process. The inclusion of this provision in new TSCA was a highly significant development that did much to contribute to the likelihood that EPA could implement a successful and informed prioritization process. For whatever reason, EPA has chosen to ignore this provision’s explicit connection to the prioritization process.

By our reading, EPA is attempting to down-play and put distance between the application of the metals Framework and the prioritization process, perhaps to allow EPA room selectively to disregard its points where it sees fit in this process.

We also believe that EPA, in substituting recitations of “considerations” as being equivalent to “criteria” in its proposal, failed to meet the TSCA Section 6(b)(1) requirement to “establish, by rule, a risk-based screening process, including criteria for designati[on]” of chemicals as high- or low-priorities. Which leads to our largest concern, which is EPA’s attempt to downplay the role of “risk-based” in the prioritization process. We do not see how it is possible to conduct a risk-based screening process without integrating hazard and exposure information at some level. EPA studiously avoids this point in what seems to be an attempt to preserve a prioritization process based on hazards and exposures considered separately and independently. In this regard, we note that the codified text includes the phrase “risk-based screening process” in the first paragraph and subsequently never returns to the concept. All subsequent references to “risk” are in the context of risk assessment, risk evaluation, non-risk factors, or EPA’s made-up catch all of “other risk-based criteria.” Congress must have intended “risk-based screening process” to be just that, a fundamental and intrinsic element of the process, and not merely a title.

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