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Assessing and Managing Chemicals under TSCA

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

Under the Toxic Substances Control Act (TSCA), as amended by the Frank R. Lautenberg Chemical Safety for the 21st Century Act, EPA has new authorities to regulate certain existing chemicals. Section 6(h) directs EPA to take action on certain persistent, bioaccumulative, and toxic (PBT) chemicals.

On this page:

EPA’s Requirements and Authorities under TSCA Section 6(h)

TSCA section 6(h) requires EPA to take expedited regulatory action under section 6(a) without a risk evaluation for PBT chemicals from the 2014 update of the TSCA Work Plan for Chemical Assessments that meet a specific set of criteria laid out in section 6(h).

The Agency must examine various ways in which exposure to PBT chemicals that meet the criteria outlined in section 6(h) are likely under the “conditions of use.” The conditions of use are the circumstances under which a chemical substance is intended, known or reasonably foreseen to be manufactured, processed, distributed in commerce, used or disposed of. Under the conditions of use for each PBT chemical, EPA will assess the exposures to the general population, potentially exposed or susceptible subpopulations, and the environment.

This information will be used to address, by regulatory action, the risks of injury to health and the environment posed by the PBT chemicals EPA identifies as meeting the requirements of section 6(h) and reduce exposure to the extent practicable. EPA must propose a rule to reduce risks and exposures from these PBT chemicals to the extent practicable no later than June 22, 2019, with a final rule to follow no more than 18 months later.

Identified PBT Chemicals and Conditions of Use

As a first step in the TSCA section 6(h) process, five PBT chemicals were identified for action by EPA according to statutory criteria. These five PBT chemicals will be the subject of the rule discussed in the preceding section. EPA first looked to chemical substances identified in the 2014 update of the TSCA Work Plan for Chemical Assessments that met the criteria for persistence and bioaccumulation described in the statute and based on the 2012 TSCA Work Plan Chemicals Methods Document. Read more about the statutory criteria.

The following five PBT chemicals are identified under the conditions specified in TSCA section 6(h):

  • Decabromodiphenyl ethers (DecaBDE), used as a flame retardant in textiles, plastics, wiring insulation, and building and construction materials;
  • Hexachlorobutadiene (HCBD), used as a solvent in the manufacture of rubber compounds and as hydraulic, heat transfer or transformer fluid;
  • Pentachlorothiophenol (PCTP), used as a mercaptan (sulfur) cross-linking agent to make rubber more pliable in industrial uses;
  • Phenol, isopropylated, phosphate (3:1), used as a flame retardant in consumer products and as lubricant, hydraulic fluid, and other industrial uses; and
  • 2,4,6-Tris(tert-butyl) phenol, an antioxidant that can be used as a fuel, oil, gasoline or lubricant additive.  

Two additional PBT chemicals met the TSCA section 6(h) criteria; however, manufacturers for these substances submitted timely requests to EPA for risk evaluations pursuant to section 6(h)(5) and are therefore not subject to the rulemaking effort. As a result of the requests, two chemicals (Ethanone, 1-(1,2,3,4,5,6,7,8-octahydro-2,3,5,5-tetramethyl-2-naphthalenyl) and Ethanone, 1-(1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethyl-2-naphthalenyl)) are excluded from the expedited action requirements under TSCA section 6(h).

Use Documents for Identified PBT Chemicals

EPA is providing background information to the public for each of the five PBT chemicals. These use documents provide a preliminary summary of available information collected by EPA on the manufacturing (including importing), processing, distribution in commerce, use, and disposal of each chemical. This is based on existing data available to EPA, including information collected under the Chemical Data Reporting rule, information from other Agency databases, other U.S. Government agencies, publicly available information from states, and a review of published literature.

Read the use documents for the five PBT chemicals identified for expedited regulatory action under TSCA section 6(h).  

Opportunities for Public Input

EPA is providing the public an opportunity to identify information specifically related to the conditions of use for the five PBT chemicals subject to the section 6(h) rulemaking that would assist the Agency in identifying potential exposure scenarios.


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 new 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

EPA has 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. EPA is requesting that any information be submitted to the dockets on or before January 12, 2018, so that the information can inform any regulatory action. 

The docket numbers can be found in the table below Additional Information, Docket Numbers, and Agency Contacts for PBTs.

Information can be submitted to the docket by one of the following methods:

  • Federal eRulemaking Portal: Found at http://www.regulations.gov. Follow the online instructions for submitting information or comments. Once submitted, this information cannot be edited or withdrawn. EPA may publish any information received to its public docket. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written statement or information. The written information should include discussion of all points you wish to make. Learn more about CBI or multimedia submissions, and general guidance on making effective comments or providing useful information.
  • Mail: Send comments to the Document Control Office (7407M), Office of Pollution Prevention and Toxics (OPPT), Environmental Protection Agency, 1200 Pennsylvania Avenue, N.W., Washington, DC 20460-0001.
  • Hand Delivery: To make special arrangements for hand delivery or delivery of boxed information, please follow instructions at http://www.epa.gov/dockets/contacts.html.

Additional Information, Docket Numbers and Agency Contacts for PBTs

Chemical CAS Number Docket ID Number Background Documents Agency Contact
Decabromodiphenyl ethers (DecaBDE) CASRN 1163-19-5 EPA-HQ-OPPT-2016-0724 Use Document for DecaBDE Cindy Wheeler
Email: Wheeler.cindy@epa.gov
Phone: (202) 566-0484
Pentachlorothiophenol (PCTP) CASRN 133-49-3 EPA-HQ-OPPT-2016-0739 Use Document for PCTP Marc Edmonds
Email: Edmonds.marc@epa.gov
Phone: (202) 566-0758
Hexachlorobutadiene (HCBD) CASRN 87-68-3 EPA-HQ-OPPT-2016-0738 Use Document for HCBD Marc Edmonds
Email: Edmonds.marc@epa.gov
Phone: (202) 566-0758
Phenol, isopropylated, phosphate (3:1) CASRN 68937-41-7 EPA-HQ-OPPT-2016-0730 Use Document for Phenol, isopropylated, phosphate (3:1) Ingrid Feustel
Email: Feustel.Ingrid@epa.gov
Phone: (202) 564-3199

Andrea Mojica
Email: Mojica.Andrea@epa.gov
Phone (202) 564-0599
2,4,6-Tris(tert-butyl) phenol CASRN 732-26-3 EPA-HQ-OPPT-2016-0734 Use Document for 2,4,6-Tris(tert-butyl) phenol Peter Gimlin
Email: Gimlin.peter@epa.gov
Phone: (202) 566-0515