Document byreDv0wBqx6w9BJb3BopKOw3

Vinyl Institute September 2024 RTP Meeting Follow Up Letter November 22, 2D24 combusted in, for example, a thermal oxidizer, to form these HAP."16 As such, the Agency narrowed its dataset to a subset of facilities and CMPUs that "manufacture chlorinated SOCMI chemicals" that include, but are not limited to, chloroform, chloroprene, ethylene dichloride, methyl chloride, trichloroethylene, and vinyl chloride monomer. As an initial matter, the Agency's rationale for identifying the six chemicals identified above as the "most prevalent" chlorinated SOCMI chemicals is not clear. Based on EPA's baseline crosswalk modeling input file," there are approximately 45 chlorinated organic chemicals emitted by HON and Polymers and Resins Industry sources that, if combusted in a control device, would likely generate D/F emissions under EPA's stated criterion of combustion of chlorine/chlorinated compounds. The Agency did not explain why it distinguished the subset of six chlorinated SOCMI chemicals out of the broader category of chlorinated organics, nor did the Agency rationalize why relying on this subset of facilities that manufacture only these 6 chlorinated chemicals was proper.18 In addition, EPA's focus on "facilities that manufacture chlorinated SOCMI chemicals" suggests that the D/F limit is applied based on the primary product of the HON facility, however, the language of 63.113(2)(5) implicates a broader scope of facilities. To review briefly, the HON rule applies to CMPUs that either (i) manufacture as a primary product one or more of certain listed SOCMI chemicals, or (ii) manufacture as a product or use as a reactant one or more listed organic hazardous air pollutants.19 For entities that meet either of these criteria, they must then determine whether they have a Group 1 process vent, looking at both the process vent characteristics at 63.107(b) through (h) or 63.107(i) and the criteria for a Group 1 process vent set out at 63.101. Based on our review, these criteria would be readily met by either a VCM or EDC HON unit. As producers of chlorinated substances, their Group 1 process vent is nearly guaranteed to "contain[] chlorine, hydrogen chloride, or [another] chlorinated compound."70 Certain producers of non-chlorinated products also have chlorinated compounds in their gas stream. Indeed, there are no qualifiers or exceptions based on the nature of the material generated (e.g., byproduct, impurity) or its concentration. Instead, the language of 63.113(a)(5) is broad, encompassing any chlorinated compounds that are contained in the qualifying Group 1 process vent. For example, a CMPU that manufactures a non-chlorinated organic substance as its primary product and owns or operates a Group 1 process vent may be 1G Dioxins and Furans MACT Floor in the SOCMI Source Category for Processes Subject to HON and Processes Subject to Group l and Group Polymers and Resins NESHAPs, Docket ID No. EPA-HQ-OAR-2022-0730-0084 at p. S. 17 Residual Risk Assessment for the Synthetic Organic Chemical Manufacturing Industry (SOCMI) Source Category in Support of the 2023 Risk and Technology Review Proposed Rule (March 2023), Docket ID No. EPA-HQ-OAR-20220730-0085 is Except that these appeared in the dataset for which the Agency had information. 40 C.F.R. 63.100(b). Note that "product" is defined to mean "a compound ur chemical which is manufactured as the intended product of the chemical manufacturing process unit. Byproducts, isolated intermediates, impurities, wastes, and trace contaminants are not considered products." 40 C.F.R. 63.101. 40 C.F.R. 64.113(a)(5). 5 Sierra Club FOIA 2025-EPA-04883 ED_018388_00000080-00011 SC_EVERSPLIT0005645