This action establishes recordkeeping and reporting requirements for uses of ozone-depleting substances as process agents and updates related definitions. Codified recordkeeping and reporting requirements will provide clear notice of information the U.S. Environmental Protection Agency collects, aggregates, and reports each year on behalf of the United States as a party to the Montreal Protocol on Substances that Deplete the Ozone Layer; effectively monitor these narrow uses in a more routine and consistent manner under the Clean Air Act; and enhance understanding of emissions of substances harmful to the stratospheric ozone layer.