EPA Issues Two Final Rules Amending MATS

On November 7, 2014, EPA announced pre-publication drafts of two sets of rules amending the Mercury and Air Toxics Standards (MATS). In the first rule, EPA finalized revisions to the startup and shutdown work practice standards. Specifically, EPA established an alternative definition of startup under which startup would end four hours after a unit begins generating electricity. Under the previously finalized definition, startup would end at 1 MW. Use of this alternative startup definition is contingent upon the following requirements: (1) use of clean fuels to the maximum extent possible; (2) engagement of the PM control device within one hour of adding coal; and (3) providing EPA with additional information in the Notification of Compliance Status such as EGU and PM control device design characteristics, PM control device efficiency, and historic changes to the unit and the control device. EPA also finalized alternative procedures for the use of sorbent trap monitoring systems during startup. In addition, EPA clarified the application of the startup and shutdown work practice standards to units venting through a common stack and established default diluent caps and default electrical loads for calculating emissions during startup and shutdown.

Second, EPA issued a direct final rule to start the process of converting all MATS electronic reporting to the Emissions Collection and Monitoring Plan System (ECMPS) Client Tool. The rule requires affected sources to submit reports in a PDF format for an interim period while EPA revises the ECMPS Client Tool to accept all reports required under MATS. EPA also issued a parallel proposed rule in conjunction with the direct final rule which EPA will proceed with in the event it receives adverse comment to the direct final rule.