This isn't a blockbuster move, but the EPA did issue some positive standards today aimed at reducing public exposure to cancer-causing gasoline fumes.
See more at http://www.examiner.com/a-557008~EPA_rule_would_cut_benzene__air_toxics_for_cars__fuel__containers.html
The rules would not require a reduction in the worst potential cancer problem from motor vehicles -- diesel fumes.
EPA has lagged in setting standards for diesel trains and boats.
And the President's recent budget request did not include enough in money to clean up dirty diesel engines.