Title IV of the Clean Air Act (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 program sets emissions limitations to reduce acidic deposition and its serious, adverse effects on natural resources, ecosystems, materials, visibility, and public health. On January 11, 1993, the Agency promulgated final rules under title IV. Several parties filed petitions for review of the rules. On April 17, 1995, the EPA and the parties signed a settlement agreement addressing continuous emission monitoring (CEM) issues. In this interim final rule, EPA is amending certain provisions of the CEM regulations to allow industry to be in compliance in situations that were not contemplated in the original rulemaking. The interim final rule allows industry additional flexibility to implement new provisions immediately that address these unforeseen situations, reduces the possibility of underestimating emissions, and also allows the public to comment upon these new provisions.