Will the Gulf of Mexico remain a dumping ground for offshore fracking waste?

For an interactive version of this Center for Biological Diversity map, click here.

When you think of a fracking site, the image that comes to mind is probably a bare-scraped well pad in a rural or maybe suburban landscape, topped with a drilling rig and other industrial infrastructure, and a fleet of trucks to haul materials needed for the controversial process that involves high-pressure injection of fluids into wells to boost oil and gas flow.

But nowadays fracking is also happening in a landscape of a very different sort: the Gulf of Mexico.

Federal documents obtained this year by the Center for Biological Diversity revealed that the Obama administration approved more than 1,200 offshore fracks in 630 different wells in the Gulf from 2010 to 2014. The fracking took place off the coasts of Texas, Louisiana, Mississippi and Alabama — with no public involvement or site-specific tests done beforehand to evaluate the environmental impact.

Given that it takes millions of gallons of water to frack a single well, and that on its way into the earth to force out oil or gas reserves the water becomes contaminated with radioactive elements, heavy metals and other toxic compounds, you might wonder: Where is all that offshore fracking wastewater going?

Directly into the Gulf, as it turns out.

A Center analysis found that oil companies operating in federal waters off the coasts of Texas and Louisiana discharged more than 76 billion gallons of fracking wastewater into the Gulf of Mexico in 2014 alone — and now the Obama administration is considering whether to allow the dumping to continue.

Back in August, the Environmental Protection Agency's Region 4 office in Atlanta released for public review a proposed Clean Water Act permit for the discharge of wastewater from offshore drilling into federal Eastern Gulf waters that raised limits on the amount of offshore fracking wastewater that can be legally dumped. The public comment period on the proposal closed last week.

The Center was among those who weighed in against the proposal. In a Sept. 17 letter, it criticized the EPA for relying on a 33-year-old study of waste fluid produced by offshore platforms. It also called on the agency to adopt a zero-discharge requirement for fracking wastewater, as is required under other offshore drilling permits.

"The EPA is endangering an entire ecosystem by allowing the oil industry to dump unlimited amounts of fracking chemicals and drilling waste fluid into the Gulf of Mexico," said Center attorney Kristen Monsell. "This appalling plan from the agency that's supposed to protect our water violates federal law and shows a disturbing disregard for offshore fracking's toxic threats to sea turtles and other Gulf wildlife."

In its study of chemicals routinely used in fracking off the California coast, the Center identified at least 10 that could kill or harm marine life, including fish and mammals. The chemicals include endocrine disrupters, neurotoxins and carcinogens. Some are bioaccumulative, meaning they build up in an organism's body and concentrate up the food chain.

The fracking-related dumping adds to the considerable burden of toxic oil and gas pollution already borne by the Gulf. The region is still recovering from the 2010 BP oil spill disaster, which dumped some 200 million gallons of crude into Gulf waters. The Gulf is also polluted by the smaller spills and chronic leaks associated with offshore drilling.

The EPA hasn't indicated a timeframe for releasing the final permit on fracking wastewater dumping. However, the current permit expired on March 31, 2015 and has been administratively extended. So the agency is expected to act relatively quickly.

Conservationists are hoping it reconsiders its proposal.

"It's the EPA's job to protect water quality from offshore fracking, not rubber-stamp the dumping of the wastewater from this dangerous, disgusting practice," Monsell said.