EPA Asked to Regulate Ship Emissions
Marine vessels are responsible for nearly 3 percent of the world's greenhouse gases — equal to the amount generated by all cars in the U.S. — and ship emissions are projected to grow by more than 70 percent by 2020 as global trade expands, according to the petitions.

"If the U.S. is to do its part in reducing the threat of global climate disruption, then EPA must limit the global warming emissions from ships that enter the ports of the United States," Brown said.