WASHINGTON — The Environmental Protection Agency is exploring whether to use the Clean Water Act to control greenhouse gas emissions, which are turning the oceans acidic at a rate that's alarmed some scientists. With climate change legislation stalled in Congress, the Clean Water Act would serve as a second front, as the Obama administration has sought to use the Clean Air Act to rein in emissions of carbon dioxide and other greenhouse gases administratively. Since the dawn of the industrial age, acid levels in the oceans have increased 30 percent. Currently, the oceans are absorbing 22 million tons of carbon...