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 dioxide a day.

Among other things, scientists worry that the increase in acidity could interrupt the delicate marine food chain, which ranges from microscopic plankton to whales.

“There are all sorts of evils associated with this,” said Robert Paine, an emeritus professor of biology at the University of Washington.

The situation is especially acute along the West Coast. Northwest winds during the summer cause upwelling, which brings deep water to the surface along the continental shelf from Queen Charlotte Sound in British Columbia to Baja California.

The water in the deep Pacific Ocean is already more acidic than shallower water is because it’s absorbed the carbon dioxide that’s produced as animals and plants decompose. Some of the deep water in the Pacific hasn’t been to the surface for 1,000 or more years.

By the end of the century, that deep water is expected to be 150 percent more acidic than it is now, and as it’s brought to the surface by upwelling, it’s exposed to even more carbon dioxide.