Final Rules Under TSCA Released for 5 PBT Chemicals
In late December 2020, the U.S. Environmental Protection Agency (EPA) issued final rules for five persistent, bioaccumulative, and toxic (PBT) chemicals. Released under the Toxic Substances Control Act (TSCA), a principal focus of these rules is to facilitate exposure reduction to the corresponding chemical substances -- 2,4,6-TTBP, decaBDE, HCBD, PCTP, and PIP (3:1).
Persistent, Bioaccumulative, and Toxic Chemicals and Final Rules
PBT chemicals are substances that are classified as persistent, bioaccumulative, and toxic.
- Persistent -- PBTs tend to resist degradation and persist within the environment.
- Bioaccumulative -- PBTs accumulate within the body, yielding increased tissue concentrations over time.
- Toxic -- PBTs generally exhibit a wide range of toxic properties.
Under TSCA, the EPA was required to take prioritized action on several PBT chemicals for the purpose of minimizing exposure and resultant risks.
PBT Chemicals
| Substance Name | CAS Number | Primary Use(s) |
|---|---|---|
| 2,4,6-tris(tert-butyl) phenol (2,4,6-TTBP) | 732-26-3 | Processing intermediate often used in fuel-related formulations |
| Decabromodiphenyl ether (DecaBDE) | 1163-19-5 | Flame retardant used in multiple products. |
| Hexachlorobutadiene (HCBD) | 87-68-3 | Byproduct chemical produced during chlorinated hydrocarbon manufacturing. |
| Pentachlorothiophenol (PCTP) | 133-49-3 | Rubber additive used to increase pliability. |
| Phenol, isopropylated phosphate (3:1) (PIP (3:1)) | 68937-41-7 | Flame retardant; plasticizer; additive in greases and lubricants, etc |
Source: U.S. Environmental Protection Agency
2,4,6-tris(tert-butyl) phenol (2,4,6-TTBP)
- Major focus of final rule: Includes prohibiting the commercial distribution of 2,4,6-TTBP and 2,4,6-TTBP-containing products at ≤ 0.3% concentration in containers smaller than 35 gallons.
Decabromodiphenyl ether (DecaBDE)
- Major focus of final rule: Forbids the manufacture and distribution of decaBDE and most products containing it, with a goal of environmental and human exposure level reduction.
Hexachlorobutadiene (HCBD)
- Major focus of final rule: Disallows the production, processing, and commercial distribution of HCBD, as well as products that contain the chemical. Acknowledges that there is inadvertent byproduct generation of HCBD in the process of chlorinated solvent production, and that this may result in some commercial distribution.
Pentachlorothiophenol (PCTP)
- Major focus of final rule: Forbids any and all PCTP production, processing, and distribution, with the exception of instances where concentrations are ≤ 1%.
Phenol, isopropylated phosphate (3:1) (PIP (3:1))
- Major focus of final rule: Disallows the manufacture and distribution of PIP (3:1) and strives to prevent its release into water during use.
The recently issued final rules for these PBTs take effect on February 5, 2021. Published in the Federal Register, the text for each of the rules can be accessed on their website and via the following links:
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