40 CFR §60.610a

1. (a)You are subject to this subpart if you operate an affected facility designated in paragraph (b) of this section that produces any of the chemicals listed in § 60.617a as a product, co-product, by-product, or intermediate, except as provided in paragraph (c) of this section.
2. (b)The affected facility is any of the following for which construction, modification, or reconstruction commenced after April 25, 2023:
   1. (1)Each air oxidation reactor not discharging its vent stream into a recovery system.
   2. (2)Each combination of an air oxidation reactor and the recovery system into which its vent stream is discharged.
   3. (3)Each combination of two or more air oxidation reactors and the common recovery system into which their vent streams are discharged.
3. (c)Exemptions from the provisions of paragraph (a) of this section are as follows:
   1. (1)Each affected facility operated with a vent stream flow rate less than 0.001 pound per hour (lb/hr) of TOC is exempt from all provisions of this subpart except for the test method and procedure and the recordkeeping and reporting requirements in § 60.614a(e) and § 60.615a(h), (i)(8), and (n).
   2. (2)A vent stream going to a fuel gas system as defined in § 63.611a.