The Environmental Protection Agency (EPA) is seeking comments to clarifications, modifications, and additions to its proposed rule titled "Strengthening Transparency in Regulatory Science," originally published on April 30, 2018 (83 FR 18768). This supplemental notice of proposed rulemaking (SNPRM) proposes that the scope of the rulemaking apply to influential scientific information as well as significant regulatory decisions. This notice proposes definitions and clarifies that the proposed rulemaking applies to data and models underlying both pivotal science and pivotal regulatory science. In this SNPRM, EPA is also proposing a modified approach to the public availability provisions for data and models that would underlay significant regulatory decisions and an alternate approach. Finally, EPA is taking comment on whether to use its housekeeping authority independently or in conjunction with appropriate environmental statutory provisions as authority for taking this action.