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Federal Register / Vol. 86, No. 3 / Wednesday, January 6, 2021 / Rules and Regulations
and mixtures for liquid lubricant and grease additives/antioxidants additives.
EPA summarizes below these uses and its conclusions regarding the exposures and the practicability of reducing such exposures.
i. Manufacture and use as an intermediate/reactant.
SI Group is currently the only large volume domestic manufacturer of 2,4,6TTBP. Historical CDR data indicate that in the 1986 to 1998 reporting years, the aggregate range of production of 2,4,6TTBP was between one and 10 million pounds per year and increased to a range of 10 to 50 million pounds per year in reporting years 2002 and 2006.
The range of production in 2012, 2013, 2014, and 2015 was confidential business information CBI in the 2016
CDR Ref. 6. There have not been any indications of substantial importation of 2,4,6-TTBP into the United States from other countries.
2,4,6-TTBP is predominantly created in chemical reactions as a co-product with a closely related alkylphenol, 2,6
ditert-butylphenol 2,6DTBP. Neither chemical can be effectively produced commercially without co-production of the other. The chemical is produced as a mixture with its co-products, primarily 2,6DTBP, at a concentration of approximately 85% 2,6DTBP and 12% 2,4,6-TTBP. Ref. 7, EPAHQ
OPPT201900800537. SI Group notes that while the reaction profile for this trans-alkylation process can be shifted based on temperature of the reaction and ratio of isobutylene to phenol, there is no feasible way to eliminate the production of 2,4,6-TTBP
in this reaction chemistry.
Approximately 94% of the 2,4,6-TTBP
produced by SI Group is consumed by the company in internal chemical processes as a feedstock for further production of other alkylphenol chemicals. This quantity of the chemical is not sold to other chemical processors;
it is used by SI Group itself. 2,4,6-TTBP
has value as a chemical intermediate in the production of dialkylphenol chemicals. Moreover, SI Group reports it is not possible to significantly suppress the formation of 2,4,6-TTBP without severely constraining the yield of other desired dialkylphenol products, therefore its manufacture has impacts beyond the commercial use of 2,4,6TTBP itself. The production of other dialkylphenol products, including alternative antioxidants, is therefore a benefit of ongoing 2,4,6-TTBP
manufacture.
As noted, approximately 94% of the 2,4,6-TTBP produced by SI Group is consumed by the company in internal processes, being used as a feedstock for
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further production of alkylphenol chemical products. The chemical reactions that use 2,4,6-TTBP as a chemical feedstock consume destroy the feedstock during the process, on site within the facility. An additional 4% of 2,4,6-TTBP produced by SI Group, which is in excess of what it requires for chemical feedstock use, is sold as a waste fuel for energy use. This excess material stream containing 2,4,6-TTBP
is used as a waste fuel for energy value, which is burned and destroyed during use Ref. 8. A hydrocarbon, 2,4,6-TTBP
has a high energy value and can be sold as a fuel. The remaining 2%
manufactured is used as a fuel additive, discussed later in this document.
SI Group notes that in the course of normal operations, the manufacturing stream of the 2,4,6-TTBP containing product is as a liquid, eliminating the possibility of fugitive and stack air dust emissions and therefore inhalation or exposure to dust EPA
HQOPPT201803140018. Based on the low vapor pressure of 2,4,6-TTBP, 6.6 104 mg Hg, EPA expects minimal chance of exposure by inhalation of vapor from such liquid Ref. 4. Dermal exposure resulting from manufacturing and processing conditions of use at chemical production facilities is expected to be minimal due to use of specified engineering controls and required personal protective equipment PPE identified by the SI Group. For example, at the manufacturer/
processing facilities, required worker PPE consists of nitrile gloves, chemicalresistant slicker suits, chemical resistant boots, respirators with face shield and hard hats; workers are trained and monitored in the correct use of their PPE. Sampling during production is accomplished using controlled sampling spigots, which prevent aerosol formation, splashing and spillage, minimizing potential worker exposure.
Controlled sampling spigots are also used for transfer activities loading and unloading EPAHQOPPT2018
03140018.
EPA has not identified releases, or potential releases from SI Groups operations, that are posing an exposure to the environment and that can be targeted for reduction with practicable measures under TSCA section 6a.
Similarly, EPA has not identified exposure or potential exposures to workers or the general population from chemical facility production and use that can be targeted for reduction with specific measures in this rule. As discussed in Unit II.F., EPA believes that in industrial settings worker protection measures used by employers reduce exposures to the extent
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practicable and EPA has determined that it is not practicable to regulate worker exposures in this rule through engineering or process controls or PPE
requirements.
The production and use of 2,4,6-TTBP
as a chemical intermediate has significance for other alkylphenol chemical products beyond the immediate uses of 2,4,6-TTBP itself, as a result of the difficulty in commercially producing these other chemicals without generating or using 2,4,6-TTBP
EPAHQOPPT201803140018, EPA did not propose to prohibit the manufacture of 2,4,6-TTBP or processing and use of 2,4,6-TTBP as a chemical intermediate. During the public comment period, EPA received no specific information addressing these issues as it might related to 2,4,6-TTBP
chemical facility operations. EPA
therefore is not imposing any additional regulatory controls for the manufacture of 2,4,6-TTBP for any use.
ii. Use for fuel treatment in refineries and fuel facilities.
As noted, of the 2,4,6-TTBP it produces, SI Group itself consumes 94%
as a chemical intermediate and sells off another 4% as waste fuel. The remaining 2% of 2,4,6-TTBP produced by SI Group is sold for use in fuel as an antioxidant. The chemical is sold in a mixture with its co-products, primarily 2,6DTBP, at a concentration of approximately 85% 2,6DTBP and 12%
2,4,6-TTBP primarily two proprietary chemical mixtures, Isonox 133 and Ethanox 4733 Ref. 7. SI Group also stated that it does not sell, supply, or distribute into commerce 2,4,6-TTBP in a pure neat form.
Most of SI Groups antioxidant product goes to use at refineries: After refining, petroleum products such as fuels quickly begin to degrade due to oxidation. A small portion of its sales volume goes to processors of aftermarket fuel treatment products discussed in the next section. SI Group does not sell its mixtures containing 2,4,6-TTBP
directly to consumers. The majority of the 2,4,6-TTBP mixtures sold are blended into the fuel at the refinery or soon after at tank farms prior to commercial distribution of the fuel.
Once blended into fuel, the resultant concentration of 2,4,6-TTBP in fuel is low, in the five to 50 ppm range.
As summarized in the proposed rule, the 2,4,6-TTBP mixture is a widely used antioxidant for jet, automotive, and marine fuels. Antioxidant additives are essential to the storage and transport of fuel, as without them, fuel quickly begins to degrade and form harmful sludge and varnish. The 2,4,6-TTBP
mixtures are the primary antioxidants
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