This action is a final promulgation of amendments to the national emission standards for hazardous air pollutants (NESHAP) for mercury emissions from mercury cell chlor-alkali plants that was promulgated in 2003. Following promulgation of the 2003 NESHAP, EPA received a petition to reconsider several aspects of the rule. In May 2008, EPA proposed amendments to the regulation for cell room fugitive mercury emissions to require recordkeeping of work practice standards for cell rooms in all facilities as well as to require instrumental monitoring of cell room fugitive mercury emissions for all plants. The 2008 proposed rule also proposed to amend aspects of the 2003 NESHAP to correct errors and inconsistencies that had been brought to EPA's attention since the NESHAP was promulgated. A supplemental proposal in March 2011 covered additional technical corrections, proposed to revise startup, shutdown and malfunction provisions, and included a proposed additional control option to prohibit mercury emissions from existing plants. This action would finalize the 2008 and 2011 proposed amendments. The rulemaking is being withdrawn because it will be addressed in the residual risk and technology review for this source category.