This action finalizes the residual risk and technology review (RTR) conducted for the Flexible Polyurethane Foam (FPUF) Production source category regulated under national emission standards for hazardous air pollutants (NESHAP). In addition, the EPA is finalizing amendments to correct and clarify regulatory provisions related to emissions during periods of startup, shutdown and malfunction (SSM); add requirements for reporting of performance testing through the Electronic Reporting Tool (ERT); clarify the leak detection methods allowed for diisocyanate storage vessels at slabstock foam production facilities; and revise the rule to add a schedule for delay of leak repairs for valves and connectors.