Persistent, Bioaccumulative, and Toxic (PBT) Chemicals under TSCA Section 6(h)

As required under section 6(h) of the Toxic Substances Control Act (TSCA), as amended by the Frank R. Lautenberg Chemical Safety for the 21st Century Act, EPA has taken action to reduce exposures to certain chemicals that are persistent, bioaccumulative and toxic (PBT). These chemicals build up, or accumulate, in the environment over time and can therefore have potential risks for exposed populations, including the general population, consumers and commercial users, and susceptible subpopulations (such as workers, subsistence fishers, tribes and children). In October 2024, EPA issued a final rule amending the rules for decabromodiphenyl (decaBDE) and phenol, isopropylated phosphate (3:1) PIP (3:1).

Recent Actions

In October 2024 EPA published a final rule revising existing rules for decaBDE and PIP (3:1). This final rule requires workplace safety protections reducing exposure to those who work with those chemicals to the extent practicable, sets a limit for their concentrations in products and articles, and further prohibits water releases. It also addresses broader implementation issues affecting the supply chains of various industry sectors including the nuclear energy, transportation, construction, agriculture, forestry, mining, life sciences, and semiconductor production sectors by revising compliance dates for certain uses of the chemicals.

The final PBT rule addresses implementation issues raised by the 2021 PIP (3:1) rule and its subsequent revisions associated with the October 31, 2024 compliance deadline for processing and distributing PIP (3:1) for use in articles and PIP (3:1)-containing articles. The final rule amends phase-in prohibitions and exclusions on processing and distribution for certain uses and further extends the compliance dates for some articles used in heating, ventilation, air-conditioning, refrigeration, and water-heating equipment, power generating equipment, laboratory equipment, commercial electronic equipment, and manufacturing equipment, including manufacturing equipment used in the semiconductor industry. EPA is not revising the October 2024 compliance date for articles not otherwise covered by (1) an exclusion from prohibition or (2) an existing or newly finalized extension to a phase-out compliance deadline. The amended phase-in prohibitions and exclusions are effective 60 days after the final rule is published in the Federal Register. EPA intends to focus its enforcement on ensuring compliance with the requirements of this final rule.

On September 27, 2024, as a bridge to the final rule effective date, EPA extended its May 2, 2023, temporary Enforcement Statement of decaBDE. Learn more about the Enforcement Statement for DecaBDE:

Extension Request for Enforcement Statement Regarding DecaBDE (pdf) (468.04 KB)
Extended Enforcement Statement Regarding DecaBDE (pdf) (251.63 KB)

Resources

View the regulations for PBTs under TSCA section 6(h).

Additional information about the 2023 proposed rule can be found in docket EPA-HQ-OPPT-2023-0376.

Read the January 2021 final rules:.

Additional information about the 2024 final rule can be found in docket EPA-HQ-OPPT-2019-0080.

Read the PIP (3:1) extension date rules:

Uses and Risk Management for Five PBT Chemicals under TSCA Section 6(h)

The Frank R. Lautenberg Chemical Safety for the 21st Century Act, enacted on June 22, 2016, includes a provision under TSCA section 6(h) requiring EPA to take expedited action on specific PBT chemicals to address risk and reduce exposures to the extent practicable. Pursuant to the statute, no risk evaluation is required for these chemicals.

Below is a summary of the uses, identified hazards, and risk management actions for each of the five PBT chemicals:

Chemical	Uses and Identified Hazards	Risk Management Actions
Decabromodiphenyl ether (decaBDE)	DecaBDE is used as an additive flame retardant in plastic enclosures for televisions, computers, audio and video equipment, textiles and upholstered articles, wire and cables for communication and electronic equipment, and other applications. DecaBDE is also used as a flame retardant for multiple applications for aerospace and automotive vehicles, including replacement parts for aircraft and cars. Learn more about decaBDE uses. Identified Hazards – DecaBDE is toxic to aquatic invertebrates, fish, and terrestrial invertebrates. Data indicate the potential for developmental, neurological, and immunological effects, general developmental toxicity, liver effects, and carcinogenicity. While many uses of DecaBDE have ceased, EPA has concluded that humans or the environment are likely exposed to DecaBDE under the conditions of use identified in the final rule.	EPA published a rule addresing decaBDE in 2021 with revisions and additional requirements published in 2024: Prohibition for the manufacture (including import), processing, and distribution in commerce of decaBDE, and products containing decaBDE, for all uses, with certain exemptions and phase outs (2021 rule). After July 6, 2022 prohibitions for use in curtains in the hospitality industry (2021 rule). After January 6, 2023 prohibitions for use in wire and cable insulation in nuclear power generation facilities, and after the end of the service life, the processing and distribution of decaBDE-containing wire and cable insulation (2021; with revisions in 2024) ; requirement of export notification for decaBDE containing wire and cable insulation for nuclear power generation facilities, including research and test reactors (2024 rule). After January 8, 2024 prohibitions on decaBDE for use in parts for new aerospace vehicles, and after the end of the aerospace vehicles' service lives, prohibitions on aerospace vehicles manufactures before January 8, 2024 and decaBDE for use in replacement parts for aerospace vehicles, and the decaBDE-containing replacement parts (2021 rule). After the end of the vehicles’ service lives or 2036, whichever is earlier, prohibitions for use in replacement parts in motor vehicles, and the replacement parts themselves (2021 rule); After the end of the pallets' service life, prohibition on distribution in commerce of plastic shipping pallets manufactured prior to the publication of the 2021 final rule that contain decaBDE (2021 rule); Exclusion for distribution and recycling of plastic that contained decaBDE before the plastic was recycled (i.e., the plastic to be recycled is from articles and products that were originally made with decaBDE), and the articles and products made from such recycled plastic so long as no new decaBDE is added during the recycling or production process (2021 rule); A regulatory threshold of 0.1% by weight for unintentional amounts of decaBDE in products and articles (2024 rule); Requirements for worker protections and recordkeeping for five years (2024); Requirements to post signs at facilities processing decaBDE-containing plastic shipping pallets (2024 rule); and Prohibitions on the release to water during manufacturing, processing, and distribution of decaBDE and decaBDE-containing products and requirements to follow any applicable regulations for preventing the release of decaBDE to water (2024 rule).
Phenol, isopropylated phosphate (3:1) (PIP (3:1))	PIP (3:1) is used as a plasticizer, a flame retardant, an anti-wear additive, or an anti-compressibility additive in hydraulic fluid, lubricating oils, lubricants and greases, various industrial coatings, adhesives, sealants, and plastic articles. As a chemical that can perform several functions simultaneously, sometimes under extreme conditions, it has several distinctive applications. Learn more about PIP (3:1) uses. Identified Hazards – PIP (3:1) is toxic to aquatic plants, aquatic invertebrates, sediment invertebrates and fish. Data indicate the potential for reproductive and developmental effects, neurological effects and effects on systemic organs, specifically adrenals, liver, ovary, heart, and lungs.	EPA published a rule addressing PIP (3:1) in 2021, with revisions and additional requirements published in 2022 and 2024: EPA prohibited processing and distribution in commerce of PIP (3:1), and products and articles containing the chemical substance, for all uses, with certain exemptions and phase outs (2021 rule); Exclusion for processing and distribution in commerce for use in aviation hydraulic fluid in hydraulic systems and use in specialty hydraulic fluids for military applications (2021 rule); Exclusion for processing and distribution in commerce for use in lubricants and greases for aviation and turbine uses and prohibitions for non-turbine and non-aerospace applications of PIP (3:1)-containing lubricants and greases after 15 years (2021; with revisions in 2024 rule); Exclusion for processing and distribution in commerce for use as an intermediate in a closed system in the manufacture of cyanoacrylate glue (2021 rule); Exclusion for processing and distribution in commerce of PIP 3:1 for use in specialized engine air filters for locomotive and marine applications (2021 rule); Exclusion for processing and distribution in commerce of finished products or articles made of plastic recycled or reused from products or articles containing PIP (3:1 ) where no new PIP (3:1) is added (i.e., the plastic to be recycled is from articles and products that were originally made with PIP (3:1)) (2021; with revisions in 2024 rule); Exclusion for processing and distribution in commerce for PIP (3:1) and PIP (3:1)-containing products for use in circuit boards and wire harnesses, and PIP (3:1)-containing circuit boards and wire harnesses (2024 rule); Exclusion for processing and distribution of articles that contain PIP (3:1), and where PIP (3:1) has not been newly added, for the purpose of repair or maintenance (2024 rule); After January 6, 2025, prohibitions on processing and distribution in commerce for use in sealants and adhesives (2021); After 15 years, prohibitions for parts for new motor vehicles and after 30 years for replacement parts (Amended 2021 exclusion with revisions in 2024 rule); After 30 years, prohibitions for parts for new aerospace vehicles, with additional time for replacement parts through the service lives of the vehicles (Amended 2021 exclusion with revisions in 2024); After October 31, 2024, prohibitions on processing and distribution in commerce of PIP (3:1) for use in articles and processing of articles , not otherwise excluded or phased out (2022); after October 31, 2026, distribution in commerce of articles (2024 rule); 5 years after publication, prohibitions on PIP (3:1) in a marine antifouling coating for use on U.S. Navy ships (2024 rule); With various phase out dates, prohibitions for new and replacement parts for manufacturing equipment, electronic equipment (personal, commercial, and laboratory), HVAC and water heating equipment, and power generating equipment (2024 rule); Requirements that persons manufacturing, processing, and distributing in commerce PIP (3:1) and products containing PIP (3:1) notify their customers of these restrictions. (2021; with revisions in 2024 rule); Prohibitions on releases to water during the manufacturing, processing and distribution of PIP (3:1) and PIP (3:1) containing products and requirements to follow existing regulations and best practices to prevent releases to water during use (2021 rule); A regulatory threshold of 0.1% by weight for unintentional amounts of PIP (3:1) in products and articles (2024); and Requirements for worker protections and recordkeeping for five years (2024 rule).
2,4,6-Tris(tert-butyl)phenol (2,4,6-TTBP)	2,4,6-TTBP is used as an intermediate/reactant in processing and is incorporated into formulations destined for fuel and fuel-related additives, as well as into formulations intended for the maintenance or repair of motor vehicles and machinery, including in oils and lubricants. Learn more about 2,4,6-TTBP uses. Identified Hazards – 2,4,6-TTBP is toxic to aquatic plants, aquatic invertebrates, and fish. Surveyed animal data indicate the potential for liver and developmental effects.	EPA prohibited the distribution in commerce of 2,4,6-TTBP and products containing 2,4,6-TTBP at concentrations above 0.3% by weight in any container with a volume of less than 35 gallons in order to effectively prevent the use of 2,4,6-TTBP as a fuel additive or fuel injector cleaner by consumers and small commercial operations (e.g., automotive repair shops, marinas). EPA also prohibited the processing and distribution in commerce of 2,4,6-TTBP, and products containing 2,4,6-TTBP, for use as an oil or lubricant additive in concentrations above 0.3% by weight regardless of container size.
Hexachlorobutadiene (HCBD)	HCBD is used as a halogenated aliphatic hydrocarbon that is produced as a byproduct during the manufacture of chlorinated hydrocarbons, particularly perchloroethylene, trichloroethylene, and carbon tetrachloride and is subsequently burned as a waste fuel. Learn more about HCBD uses. Identified Hazards – HCBD is toxic to aquatic invertebrates, fish, and birds, and has been identified as a possible human carcinogen. Data indicate the potential for renal, reproductive, and developmental effects.	EPA prohibited the manufacturing (including import), processing, and distribution in commerce of HCBD and HCBD-containing products or articles, except for the unintentional production of HCBD as a byproduct during the production of chlorinated solvents, and the processing and distribution in commerce of HCBD for burning as a waste fuel.
Pentachlorothiophenol (PCTP)	PCTP is used to make rubber more pliable in industrial uses. Learn more about PCTP uses. Identified Hazards – PCTP is toxic to protozoa, fish, terrestrial plants, and birds. Data for analogous chemicals (pentachloronitrobenzene and hexachlorobenzene) indicate the potential for liver and reproductive effects. However, no animal or human hazard data has been identified.	EPA prohibited the manufacturing (including import), processing, and distribution in commerce of PCTP or, and PCTP-containing products or articles, unless PCTP concentrations are at or below 1% by weight.

Additional Information

Public Webinars

On December 12, 2024 EPA hosted a public webinar on the 2024 final rule for decaBDE and PIP (3:1). During this webinar, EPA presented an overview of the final rule and responded to inquiries.

View EPA's presentation (pdf) (451.08 KB)

On December 14, 2023 EPA hosted a public webinar on the 2023 proposed rule for decaBDE and PIP (3:1). During this webinar, EPA presented an overview of the proposed rule and received public comments to inform the development of the 2024 final rule.

Read the transcript of the webinar.

On September 7, 2017 EPA hosted a webinar, “Use Information for Persistent, Bioaccumulative, and Toxic (PBT) Chemicals Under TSCA Section 6(h).” This webinar provided background on the requirements for PBT chemicals under amended TSCA and explained to interested parties the process for gathering use and exposure information the five PBT chemicals.

Public Dockets

The following public dockets are available for more information on EPA's regulations of the PBT chemicals under TSCA:

EPA-HQ-OPPT-2019-0080: Five PBT 2021 final rules.
EPA-HQ-OPPT-2021-0598: PIP (3:1) compliance date extension.
EPA-HQ-OPPT-2023-0376 DecaBDE and PIP (3:1) 2023 proposed and 2024 final rule.

EPA also established public dockets for public comment on the March 2021 notice requesting input on the five PBT rules :EPA-HQ-OPPT-2021-0202.

Additionally, EPA established public dockets for each of the five PBT chemicals to facilitate receipt of information on exposure and use which may be useful to the Agency’s rulemaking effort. To read the comments EPA received, visit the docket for each chemical.

Letter Peer Reviews of Exposure and Hazard Information

In May 2018, EPA conducted letter peer reviews of exposure and hazard information for the five PBT chemicals selected for expedited review under the amended TSCA. EPA also accepted written comments on the charge questions and other documents to be considered by the peer reviewers. These materials are available in docket EPA-HQ-OPPT-2018-0314.

Learn more about letter peer reviews for the five PBT chemicals.