To achieve a more stringent ambient-air ozone standard promulgated in 1997, the U.S. EPA has established summer NOx emissions limits for fossil-fired electric power generating units in the Ozone Transport Rulemaking region, consisting of 22 eastern and midwestern states and the District of Columbia. These jurisdictions are required to submit State Implementation Plans by September 1999 in response to EPA's rule, with compliance required by 2007. There are 1757 affected units in this region. In the present study, projected state-by-state growth rates for power production are used to estimate power production and NOx emissions by unit in the year 2007. NOx emissions reductions expected by January 1, 2000 due to Title IV compliance are estimated, leaving a substantial balance of emissions reductions to be achieved by post-combustion NOx control. Cost estimates are developed for achieving these remaining reductions.