The U.S. Environmental Protection Agency (EPA) November 26 proposed tightening the federal Clean Air Act (CAA) standard for ozone from the current 75 parts per billion (ppb) to between 65 and 70 ppb, with the option of going as low as 60 ppb.  Consequences of this proposal would impair the transportation construction community as any of these options could increase the number of counties out of compliance with the CAA and, as a result, federal highway funds scheduled for use in noncomplying counties could be withheld. While the EPA is required by law to review the ozone standard every five years, the agency is not required to tighten it.  However, keeping the current standard does not appear to be an option EPA is willing to consider as part of their review.  The agency has also announced a series of public hearings on the proposal in January 2015.  ARTBA will carefully review and submit comments on EPA’s proposal, as well as participate in the public hearings.