Persistent, Bioaccumulative, and Toxic (PBT) Chemicals under TSCA Section 6(h)
As required under the Toxic Substances Control Act (TSCA), as amended by the Frank R. Lautenberg Chemical Safety for the 21st Century Act, EPA issued five final rules on January 6, 2021, to reduce exposures to certain chemicals that are persistent, bioaccumulative and toxic (PBT). These chemicals build up 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).
Following issuance of Executive Order 13990 (Protecting Public Health and the Environment and Restoring Science to Tackle the Climate Crisis) and other administration priorities, EPA requested and received comment on the January 2021 PBT rules. Specifically, EPA asked for comment on additional actions that could be taken to reduce exposures to these PBT chemicals to the extent practicable.
In September 2021, EPA announced its intent to initiate a new rulemaking and anticipates proposing new rules in the Spring of 2023 for five PBT chemicals that are the subject of final risk management rules under TSCA.
Additionally, in March 2022, EPA issued a final rule further extending the compliance dates for the prohibitions on processing and distribution and the associated recordkeeping requirement of one of these PBT chemicals, phenol, isopropylated phosphate (3:1) (PIP (3:1)) when used in certain articles until October 31, 2024. This action was based on the detailed information provided during the 60-day public comment period for EPA’s October 2021 proposal. This final rule is effective upon publication.
- Learn more about the compliance date extension for PIP (3:1)
- Read the January 2021 final rules.
- Additional information about the final rules can be found in docket EPA-HQ-OPPT-2019-0080.
On this page:
- Uses and risk management for five PBT chemicals under TSCA section 6(h)
- Decabromodiphenyl ether (DecaBDE)
- Phenol, isopropylated phosphate (3:1) (PIP (3:1))
- 2,4,6-Tris(tert-butyl)phenol (2,4,6-TTBP)
- Hexachlorobutadiene (HCBD)
- Pentachlorothiophenol (PCTP)
- Additional information
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. EPA identified five PBT chemicals for expedited action in 2016, following criteria outlined in section 6(h) of TSCA and issued a proposed rule in 2019. EPA issued final rules on January 6, 2021. Pursuant to the statute, no risk evaluation was 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 prohibited the manufacture (including import), processing, and distribution in commerce of decaBDE, and products containing decaBDE, for all uses, except for the following:
Phenol, isopropylated phosphate (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.
EPA prohibited processing and distribution in commerce of PIP (3:1), and products and articles containing the chemical substance, for all uses, except for the following:
EPA required that persons manufacturing, processing, and distributing in commerce PIP (3:1) and products containing PIP (3:1) notify their customers of these restrictions. However, the compliance date for recordkeeping associated with certain consumer and commercial PIP (3:1)-containing articles mentioned above is October 31, 2024.
EPA also prohibited releases to water from the remaining manufacturing, processing, and distribution in commerce activities, and requiring commercial users of PIP (3:1) and PIP (3:1)-containing products to follow existing regulations and best practices to prevent releases to water during use.
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. The studies presented in this document demonstrate these hazardous endpoints. EPA has concluded that exposure to 2,4,6-TTBP under the conditions of use is likely.
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.
|PCTP, which is also called 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 manufacture (including import), processing, and distribution in commerce of PCTP, and products or articles containing PCTP, unless PCTP concentrations are at or below 1% by weight.|
EPA conducted letter peer reviews of exposure and hazard information for the five PBT chemicals. 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.
On Thursday, September 7, 2017, at 2 pm EDT, 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.
- DecaBDE – EPA-HQ-OPPT-2016-0724
- PIP (3:1) – EPA-HQ-OPPT-2016-0730
- 2,4,6-TTBP – EPA-HQ-OPPT-2016-0734
- HCBD – EPA-HQ-OPPT-2016-0738
- PCTP – EPA-HQ-OPPT-2016-0739
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).