EPA Releases Default Values Guide for TSCA New Chemical Risk Assessments

On November 24, 2025, EPA released a guide listing common “default values” for environmental releases and worker exposures used by the agency in risk assessments of new chemical substances under the Toxic Substances Control Act (TSCA).

What Are Default Values?

Default values are assumed engineering values used by EPA when chemical-specific information is unavailable.  For example, the guide shows that EPA assumes that 3% of a new chemical substance remains in a 55-gallon drum as residue if the drum is emptied by pumping, while 0.6% remains if it is emptied by pouring.

“This initiative marks another step forward in the agency’s ongoing commitment to transparency by providing valuable information to stakeholders involved in the review of new chemicals,” an EPA press release states.  “The publication of the default values is also expected to improve efficiency, reducing the likelihood that submissions need to be reworked or resubmitted.”

What’s Included

The guide includes default values used to model environmental releases the following situations:

  • Transferring liquid material to/from transport containers
  • Transferring solid material to/from transport containers
  • General industrial/commercial processes
  • Transferring solid materials (e.g., transferring/unloading/loading of solid powders)
  • Industrial/commercial use of coatings

The guide also includes default values used to model inhalation or dermal worker exposures from situations involving handling solids (e.g., raw materials or formulated products) or liquids containing the new chemical substance.

EPA provides two example situations demonstrating how the default values are applied to real-world scenarios, including how the assumptions change if submitters provide additional information.

In the press release, EPA said that it considers the guide to be an evolving document that may be updated in the future.  The guide, and other guidance for new chemical submissions, can be found at EPA’s New Chemicals Division Reference Library.

Union Says EPA’s New Chemicals Rule Fails Transparency Mandate Under TSCA

EPA’s 2024 new chemicals procedural rule fails to satisfy Congress’s intent that Toxic Substances Control Act (TSCA) new chemical and significant new use reviews be transparent, a workers union told the Ninth Circuit on October 16, 2025.

In its opening brief, United Automobile, Aerospace & Agricultural Implement Workers of America (UAW) cites its own experience attempting to secure information about the health hazards facing employees in one of its bargaining units.  Although a UAW representative was told by the company that it was producing two new chemicals, he was unable to locate any information on them on ChemView, EPA’s database of new chemical information, the brief states.

“EPA’s disclosures about new chemicals do not routinely include…two key factual components – employer name and location – since the employer is not necessarily the submitter, the submitter’s name is often claimed as CBI, and facility location is not among the fields that can be searched in ChemView,” UAW states.

“Without access to information about who may produce a new chemical and where it may be manufactured, potentially exposed workers and their unions cannot – as a practical matter – engage with EPA before the Agency imposes occupational controls that may or may not adequately protect the workers,” which is their right under the National Labor Relations Act (NLRA), the brief reads.

UAW and other unions jointly raised these concerns in August 2023 comments on EPA’s proposed new chemicals procedural rule.  However, according to the brief, EPA completely ignored the comment during the rulemaking—a violation of the Administrative Procedure Act (APA), according to the brief.

Proposed Disclosure Requirements

In their 2023 comments, the unions proposed a mechanism through which EPA could mandate the disclosure of information to unions or workers, which they argue would preserve the information’s confidential status.

“EPA can require entities submitting new chemical or significant new use applications to notify their affected employees that they are submitting these applications and to make the applications, the health and safety studies submitted with the application, and any risk evaluations completed by EPA available to the employees and their unions upon request, contingent on the requester agreeing to confidentiality protections,” the comments state.

Reiterating arguments made in the comments, UAW’s brief contends that this process would not run afoul of TSCA section 14, which governs CBI protections: “While Section 14, like [Freedom of Information Act (FOIA)]  Exemption 4, allows EPA to withhold confidential information submitted to the federal government…neither Exemption 4 nor TSCA Section 14 prohibits EPA from mandating third party disclosure of CBI.”

UAW argues that unions and workers routinely enter into similar confidentiality agreements to access other sensitive information, like financial information about corporate profits.  The union also points to a 1985 Third Circuit decision, which it argues “directed OSHA to permit direct employee access to claimed trade secret information if the workers signed a confidentiality agreement” under OSHA’s Hazard Communication Standard.

Case Details

The suit is consolidated with other challenges to the 2024 new chemicals procedural rule brought by environmental groups.  As discussed in a previous post, those groups are arguing that the rule’s failure to categorically exempt new persistent, bioaccumulative, and toxic chemicals (PBTs) from certain expedited reviews violates TSCA.

The case is Alaska Community Action on Toxics v. EPA, No. 25-158 (9th Cir.), filed 1/10/2025.

ACI Pushes Senate to Address EPA Bottlenecks in New Chemical Reviews

In an October 23, 2025, letter to leaders of the Senate Environment and Public Works Committee and its Subcommittee on Chemical Safety, the American Cleaning Institute (ACI) called for “targeted changes” to the Toxic Substances Control Act (TSCA) to accelerate new chemical reviews under the statute.

“ACI members are experiencing considerable challenges with [EPA’s] ability to meet its statutory deadlines under [TSCA], namely, to review and make final determinations on new chemicals within 90 days,” hindering innovation and the development of more eco-friendly products, the letter reads.

ACI also asked the committee to consider the “adverse impact” of significant new use rules (SNURs), which it claims are being applied to restrict “most” new chemicals.

“EPA has taken this route as TSCA requires EPA to consider ‘reasonably foreseen’ uses in new chemical reviews,” ACI wrote.  “The lack of a clear definition in the TSCA for the term ‘reasonably foreseen’ has led EPA staff to take an overly conservative approach that focuses heavily on theoretical hazards instead of utilizing a risk-based approach that prioritizes the specific conditions of use provided by manufacturers about the intended use of new chemistries.”

Meanwhile, ACI’s general counsel, Douglas Troutman, has been nominated by President Trump to lead EPA’s Office of Chemical Safety and Pollution Prevention. The Senate Environment and Public Works Committee advanced his nomination to the full Senate on October 29, 2025, in a party-line vote.

Groups Challenge EPA Rule Allowing PBTs in TSCA Exemption Reviews

New persistent, bioaccumulative, and toxic chemicals (PBTs) should not be eligible for expedited reviews under the Toxic Substances Control Act (TSCA) known as the low volume exemption (LVE) and low releases and exposures exemption (LoREX), environmental groups told the Ninth Circuit on October 17, 2025.

The lawsuit challenges EPA regulations finalized in December 2024 that allow companies to continue to continue to apply those exemptions for certain PBTs.  In their opening brief, the petitioners argue that the rule violates TSCA’s requirement that exemptions protect against unreasonable risk.

“The record, including EPA’s own findings, establishes that the category of new PBTs may—indeed, will likely—present unreasonable risk even when complying with the terms of the LVE and LoREX Exemptions,” the brief states.

Disputed Eligibility Standards

The 2024 rule made PFAS categorically ineligible for the exemptions, as well as PBTs “with anticipated environmental releases and potentially unreasonable exposures to humans or environmental organisms.”  The petitioners contend that this “turns the statute on its head” because it requires that EPA affirmatively determine “that a specific PBT is unsafe” for it to be ineligible.

“In effect, the rule treats an absence of evidence as a reason to expedite the approval of a new PBT chemical, rather than a reason to deny an exemption application,” their brief states.

EPA justified its decision to allow certain PBTs to remain eligible by suggesting that PBT use may not always result in exposure, “such as chemical substances used in a closed system to make semiconductors.”  In the rule, EPA also stated that it “expects that most exemptions for PBT chemical substances will not be granted.”

The petitioners, however, describe EPA’s “zero-release-zero-exposure” scenarios as “fanciful.”   All “new PBTs will eventually be released into the environment, cause exposures, and thereby result in serious injury,” they argue.

Speedier Reviews

LVE and LoREX applications are subject to a 30 day review period, compared to 90-to-180 days for standard reviews, though review backlogs mean reviews often take much longer in practice.  The petitioners claim that LVE and LoREX reviews are less “detailed and comprehensive” than standard reviews, and observe that EPA does not require testing or impose additional restrictions on approved exemption applications—incentivizing companies to use them.

Publicly available EPA data shows that 221 valid LVEs were submitted in fiscal year 2025, which was greater than the number of standard review applications.  No LoREX submissions were received during the year, however.

In August 2025, EPA announced that it had made substantial progress on the LVE backlog thanks to process improvements.  However, its continued progress may be jeopardized by the ongoing government shutdown.

More on EPA’s 2024 new chemicals procedural rule can be found in a previous post.  The case is Alaska Community Action on Toxics v. EPA, No. 25-158 (9th Cir.), filed 1/10/2025.

EPA to Fast-Track Chemical Reviews for AI and Data Center Projects

EPA will prioritize review of premanufacture notices (PMNs) for chemicals tied to artificial intelligence (AI) and data center projects, the agency announced on September 18, 2025.

“We inherited a massive backlog of new chemical reviews from the Biden Administration which is getting in the way of projects as it pertains to data center and artificial intelligence projects,” EPA Administrator Lee Zeldin said.  “The Trump EPA wants to get out of the way and help speed up progress on these critical developments, as opposed to gumming up the works.”

The policy implements President Trump’s Executive Order 14318, “Accelerating Federal Permitting of Data Center Infrastructure,” which directs the agency to expedite permitting for qualifying projects under a variety of environmental statutes, including the Toxic Substances Control Act (TSCA).

What Projects are Eligible?

Two types of projects can qualify for expedited review:

  1. Data center projects requiring more than 100 megawatts (MW) of new load dedicated to AI inference, training, simulation, or synthetic data generation.
  2. Covered component projects, which include the materials, products, and infrastructure needed to build or operate such facilities—such as energy infrastructure, power plants, semiconductors, networking equipment, and data storage systems or software.

To be eligible, a project must also meet at least one of the following criteria:

  • A commitment of $500 million or more in capital expenditures.
  • An incremental electric load addition of more than 100 MW.
  • Direct relevance to national security.
  • Official designation as a qualifying project by a federal department.
How to Request Priority Review

According to updated EPA guidance, the new priority review process will take effect on September 29, 2025. To request it, PMN submitters must:

  • Attach a cover letter to their PMN submission via EPA’s Central Data Exchange (CDX).
  • Identify the specific data center or covered-component project the chemical will support.
  • Show that the project meets at least one of the executive order’s qualifying criteria.
  • Provide supporting documentation, such as permitting records, project announcements, or letters of support, plus details on how the chemical will be used.

EPA has posted detailed instructions for companies seeking priority review on its PMN guidance webpage.

Coalition Letter to Congress Calls for Streamlined TSCA Chemical Reviews

A collection of over 100 trade associations is calling on Congress to reform the Toxic Substances Control Act (TSCA) to “ensure a regulatory system that balances human health and environmental concerns with domestic supply chain and innovation needs and supports growth in our manufacturing sector.”

The American Alliance for Innovation (AAI) letter, sent to congressional leaders on September 8, 2025, suggests a number of “improvements and clarifications” to the statute, including:

  • Ensuring timely and predictable reviews of new chemicals;
  • Avoiding unnecessary regulation, including overuse of Consent Orders (COs) and Significant New Use Rules (SNURs) that discourage adoption of innovative and sustainable chemicals;
  • Following a risk-based approach to regulating a chemical’s intended use in commerce that is rooted in actual uses and real-world scenarios;
  • Strengthening the scientific standards included in TSCA for what constitutes “the weight of the scientific evidence;” and,
  • Providing additional clarity to other sections of TSCA that govern testing, regulatory petitions, and data sharing.

AAI suggests that these changes be incorporated into any legislation to extend TSCA’s fee authority, which expires at the end of fiscal year 2026.

EPA Withdraws SNURs for 18 Chemicals Following Community Challenge

EPA has withdrawn proposed Toxic Substances Control Act (TSCA) significant new use rules (SNURs) for 18 chemical substances developed by Chevron USA, after a community organization argued that EPA’s regulation failed to address “extreme health risks” to residents near industrial sites in Mississippi.

EPA previously withdrew the corresponding TSCA section 5(e) order and premanufacture notice (PMN) determinations for the chemicals in December 2024, following a voluntary remand in a D.C. Circuit challenge to the order, Cherokee Concerned Citizens (CCC) v. EPA, No. 23-01096.

“Consistent with the withdrawal of the TSCA 5(e) Order” and received comments, “EPA is withdrawing the proposed rules,” EPA’s July 9, 2025, Federal Register notice states.

Petitioner Arguments

In the associated case, CCC argued that the 5(e) order—which restricted uses of the chemicals beyond those proposed by Chevron in its PMNs and mandated worker protections—did nothing to protect fenceline communities from health risks identified by EPA in its analyses.

“[T]he Order summarizes numerous risks that exceed by orders of magnitude the risk levels EPA has consistently defined as ‘unreasonable’ and then recites trivial requirements for Chevron’s production and use of the waste plastic chemicals that could not possibly mitigate the risks to people living near the refinery,” CCC’s opening brief stated.

Among the risks identified by EPA was a one-in-four chance that people exposed to long-term air pollution generated by one chemical would develop cancer—a risk 250,000 times greater than EPA’s one-in-a-million cancer risk benchmark, according to CCC.  In its motion for voluntary remand, EPA acknowledged it had “substantial concerns that the Section 5 Order may have been made in error.”

The SNURs identified significant new uses to include uses that did not conform to the 5(e) order, as well as the manufacture or processing of the chemicals using feedstocks containing PFAS or other chemicals of concern.

The PMNs stated that the chemicals would be used as a fuel, fuel additive, fuel blending stock, or refinery feedstock.  EPA reports that their manufacture had not yet commenced at the time the order was withdrawn.

Phil Moffat to Present at Chemical Watch Regulatory Summit North America 2025

Verdant Law is pleased to announce that Phil Moffat will speak at Chemical Watch’s Regulatory Summit North America 2025, which will take place September 15–18 in Alexandria, Virginia.

On September 15 at 11:50 am, Mr. Moffat will present on the Trump administration’s implementation of the Toxic Substances Control Act (TSCA) New Chemicals Program.  At 12:40 pm, Mr. Moffat will join an extended Q&A panel titled “Stakeholder perspectives on new chemical trends.”

Registration for the summit is open for both in-person and virtual attendance.

Update – September 16, 2025

Slides from Mr. Moffat’s presentation, “Balancing Innovation and Risk Management: TSCA’s New Chemical Review Process,” are now available here.

Environmental Groups Urge EPA to Block Motiva Chemical Applications

Environmental groups are urging EPA to deny 17 new chemical applications submitted by Motiva Enterprises for production at its refinery in Port Arthur, Texas, arguing that the new chemicals would endanger nearby residents who already experience disproportionately high exposures to pollution.

Joint comments on the premanufacture notices (PMNs) were submitted by Community In-Power and Development Association and Earthjustice on March 26.  The groups argue that at minimum, there is sufficient cause for EPA to conclude that the chemicals “may present” an unreasonable risk—triggering the agency’s duty under the Toxic Substances Control Act (TSCA) to prohibit or restrict them.

The comments claim that the publicly available versions of the PMNs provide evidence of carcinogenicity and other serious health harms, even though Motiva “unlawfully withheld and redacted critical information” from the submissions.  These hazards are compounded by high estimated production volumes, which the groups say exceed 450 million pounds annually across the 17 chemicals.

Much of the focus is on Port Arthur, “one of the nation’s most severely polluted communities.”  Decades of chemical exposures have led to elevated rates of cancer, heart disease, and respiratory illnesses, especially in the predominantly Black neighborhoods adjacent to the Motiva plant and other industrial facilities, according to the comments.  EPA should treat these neighborhoods as a “potentially exposed or susceptible subpopulation” under amended TSCA, the comments argue.

The groups also point to what they call “Motiva’s long history of malfunctions, accidents, and other chemical incidents” at the Port Arthur site, arguing that future incidents are “reasonably foreseen” and therefore fall within the “conditions of use” EPA must consider in evaluating the PMNs.

All 17 PMNs were submitted by Motiva in January 2025.  Most are generically described as “Hydrocarbon, processed.”

EPA Revises New Chemicals Review Process

On December 18, 2024, EPA published a final rule revising the new chemicals review provisions under the Toxic Substances Control Act (TSCA).  The rule:

  • Requires an EPA determination on each notice before a submitter may begin manufacturing or processing the chemical, as mandated by amended TSCA;
  • Clarifies the level of detail expected for premanufacture notices (PMNs), significant new use notices (SNUNs), and exemption notices;
  • Modifies EPA’s review process for PMNs and SNUNs, including procedures for handling incomplete or inaccurate submissions;
  • Revises the regulations for low volume exemptions (LVEs) and low releases and low exposures exemptions (LoREXs) to require submitters to wait for EPA approval prior to manufacture; and
  • Prohibits PFAS and certain PBTs from qualifying for LVE and LoREX exemptions.

EPA’s clarification of existing PMN requirements includes greater detail on products that would contain the chemical, manufacturing processes, worker exposures, and releases.  To effectuate these changes, EPA is introducing new reporting fields to the PMN form.

One key change to the procedures for handling incomplete submissions is that EPA will now declare a submission incomplete and restart the review process if a submitter provides required information that was known or reasonably ascertainable at the time of the original submission.  Previously, EPA’s “longstanding practice” was to accept the amendments along with a request to suspend the review period.

Restrained Approach

The final rule largely follows EPA’s May 2023 proposal.  In response to comments, EPA agreed to proactively notify current LVE and LoREX holders about significant new use rules (SNURs) that apply to their chemicals, rather than only providing notice prospectively as originally proposed.  EPA also agreed to expressly codify that the agency has authority to strengthen protections in TSCA section 5 orders based on new information from any source.

Environmental organizations urged EPA to revoke previously granted LVEs for PFAS, but the agency declined to do so in the rule.  However, EPA left open the possibility of future revocations, stating that it “may take future action on a case-by-case basis.”  In general, EPA has not granted new LVEs for PFAS since 2021.

Industry groups, on the other hand, unsuccessfully pushed for more streamlined TSCA section 5 notices.  Among their rejected proposals was a request that EPA only require specific data elements on a case-by-case basis.

The rule takes effect January 17, 2025, shortly before the presidential transition.