The owner or operator of an engine is subject to requirements under 40 CFR Part 63 Subpart ZZZZ, as applicable.* The owner or operator of an engine is subject to requirements, as applicable, under: 40 CFR Part 60 Subpart IIII*; or 40 CFR Part 60 Subpart JJJJ*. * In May 2015, the United States Court of Appeals for the District of Columbia Circuit vacated paragraphs 40 CFR 60.4211(f)(2)(ii)—(iii), 60.4243(d)(2)(ii)—(iii), and 63.6640(f)(2)(ii)—(iii). Therefore, engines subject to this chapter do not have to comply with those provisions.