(a) A new incineration unit is an incineration unit subject to this subpart that meets any of the criteria specified in paragraphs (a)(1) or (2) of this section, except as specified in paragraph (a)(3) of this section.

(1) Commenced construction after August 31, 2020.

(2) Commenced reconstruction or modification on or after December 29, 2025.

(3) If your incineration unit is a very small municipal waste combustion unit or institutional waste incineration unit and commenced construction, reconstruction, or modification on or before August 31, 2020, or reconstruction or modification on or before December 29, 2025, and you must meet one of the following:

(i) If your incineration unit commenced construction after December 9, 2004, or commenced reconstruction or modification after June 16, 2006, and met the applicability of paragraph (a)(1) or (a)(2) of this section before December 29, 2025, your unit is considered a new incineration unit and remains subject to the emission limitations of table 1 and applicable requirements of this subpart until the unit becomes subject to the requirements of an approved state plan or federal plan that implements subpart FFFF of this part (Emission Guidelines and Compliance Times for Other Solid Waste Incineration Units), except as provided in paragraph (a)(3)(iii) of this section.

(ii) If your incineration unit commenced construction on or before December 9, 2004, or commenced reconstruction or modification on or before June 16, 2006, and did not meet the applicability of paragraph (a)(1) or (a)(2) of this section as of December 29, 2025, then your unit is considered an existing incineration unit and is subject to the requirements of an approved state plan or federal plan that implements subpart FFFF of this part (Emission Guidelines and Compliance Times for Other Solid Waste Incineration Units), except as provided in paragraph (a)(3)(iii) of this section.

(iii) If you met the applicability of § 60.2015(a)(3) or § 40 CFR 60.2550(a) as of December 29, 2025, then your unit is considered a commercial and industrial solid waste incineration unit and remains subject to the applicable requirements, until the unit becomes subject to the requirements of an approved state plan or federal plan that implements subpart FFFF of this part (Emission Guidelines and Compliance Times for Other Solid Waste Incineration Units).

(b) This subpart does not affect your incineration unit if you make physical or operational changes to your incineration unit primarily to comply with the emission guidelines in subpart FFFF of this part. Such changes do not qualify as reconstruction or modification under this subpart.