Finding of Failure To Attain and Reclassification of the Missouri Portion of the St. Louis Nonattainment Area as Serious for the 2015 Ozone National Ambient Air Quality Standards

The Environmental Protection Agency (EPA) is determining that the Missouri portion of the St. Louis, MO-IL bi-State nonattainment area failed to attain the 2015 ozone National Ambient Air Quality Standards (NAAQS) by the applicable attainment date. The effect of failing to attain by the applicable attainment date is that the area will be reclassified by operation of law to "Serious" nonattainment for the 2015 ozone NAAQS on December 31, 2024, the effective date of this final rule. This action fulfills the EPA's obligation under the Clean Air Act (CAA) to determine whether ozone nonattainment areas attained the NAAQS by the attainment date and to publish a document in the Federal Register identifying each area that is determined as having failed to attain and identifying the reclassification. The corresponding action for the Illinois portion of the St. Louis, MO-IL bi-State area is being taken separately.