EPA's denial of California waiver request spawns cross-continent tug-of-war.

The article reports on the move of the U.S. Environmental Protection Agency (EPA) to deny California's request for a waiver to regulate greenhouse gases (GHGs) from motor vehicles in the U.S. It says that the decision of the EPA administrator has prompted lawsuits by California, 18 other states, and several environmental groups. It is noted that California requested the waiver to curb GHG emissions to combat global warming.