Environmental Protection Agency Administrator Gina McCarthy testifies at an oversight hearing of the Senate Environment and Public Works Committee on Capitol Hill in Washington on July 23.
J. Scott Applewhite/AP
November 26, 2014 The rules would lower the threshold for ozone from 75 parts per billion to between 65 ppb and 70 ppb. They are likely to be opposed by industry groups as well as Republicans.
September 11, 2014 NASA says that a ban on CFCs enacted in the 1980s has contributed to a 4 percent rebound since 2000 in atmospheric ozone in mid-northern latitudes.
September 2, 2011 The president says "reducing regulatory burdens and regulatory uncertainty, particularly as our economy continues to recover" prompted his administration to rethink.
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