Title IV of the Clean Air Act (CAA or the Act), as amended by the Clean Air Act Amendments of 1990, authorizes the Environmental Protection Agency (EPA or Agency) to establish the Acid Rain Program. The Acid Rain Program and the provisions in today's final rule benefit the environment by preventing the serious, adverse effects of acidic deposition on natural resources, ecosystems, materials, visibility, and public health. The program does this by setting emissions limitations to reduce acidic deposition precursor emissions. On January 11, 1993, the Agency promulgated final rules, including the final continuous emission monitoring (CEM) rule under title IV. On May 17, 1995, the Agency published a direct final rule to make the implementation of the program simpler. Furthermore, on May 17, 1995 the Agency published an interim final rule and took comment on the provisions in the interim final rule. In this final rule, EPA is amending certain provisions of the CEM regulations in response to public comments received on the direct final and interim final rules. These amendments will streamline the rule and increase implementation flexibility for the affected industry.