Section 721.11492 - 2-Butanone, 3-methyl-, peroxide(a)Chemical substance and significant new uses subject to reporting.(1) The chemical substance identified as 2-butanone, 3-methyl-, peroxide (PMN P-17-294, CAS No. 182893-11-4) is subject to reporting under this section for the significant new uses described in paragraph (a)(2) of this section.(2) The significant new uses are: (i)Protection in the workplace. Requirements as specified in § 721.63(a)(1), (a)(2)(i), (a)(3) through (6), and (c) . When determining which persons are reasonably likely to be exposed as required for § 721.63(a)(1) and (4) , engineering control measures (e.g., enclosure or confinement of the operation, general and local ventilation) or administrative control measures (e.g., workplace policies and procedures) shall be considered and implemented to prevent exposure, where feasible. For purposes of § 721.63(a)(5) , respirators must provide a National Institute for Occupational Safety and Health (NIOSH) assigned protection factor (APF) of at least 50. For purposes of § 721.63(a)(6) , the applicable airborne form of the substance is particulate (including solids or liquid droplets).(ii)Industrial, commercial, and consumer activities. It is a significant new use to use the substance other than as an organic peroxide polymerization initiator.(b)Specific requirements. The provisions of subpart A of this part apply to this section except as modified by this paragraph (b). (1)Recordkeeping. Recordkeeping requirements as specified in § 721.125(a) through (e), and (i) are applicable to manufacturers and processors of this substance.(2)Limitation or revocation of certain notification requirements. The provisions of § 721.185 apply to this section. 86 FR 30194 , June 7, 2021