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There’s coal waste in Puerto Rico’s groundwater.

Six months after Hurricane Maria slammed into the U.S. island territory, 11 percent of residents still don’t have power; the poverty rate has increased from 44.3 percent to 52.3 percent; and 40 to 60 percent of small businesses have permanently closed. Now, a joint report from La Perla del Sur and the Center for Investigative Journalism has found “signs of radioactivity, in addition to traces of arsenic, chromium, selenium and molybdenum” in the groundwater surrounding a coal-fired power plant in Guayama, a southern city of 42,000 people.

We’ve called attention to this plant before. It’s owned by AES Puerto Rico and contains a five-story-tall pile of toxic coal ash, which sat uncovered during Maria’s 140-mph winds and intense rainfall. Environmental advocates worried that the storm caused ash—which contains high levels of arsenic, mercury, and chromium—to blow off the pile or seep into groundwater.

The joint report confirms those fears, revealing that a study of AES’s groundwater conducted by federal Environmental Protection Agency “shows that the ash mountain is releasing large amounts of chemicals into the groundwater,” and that the groundwater is flowing away from the power plant and toward the sea.

Since the story was published, Puerto Rico’s environmental quality board has given AES ten days to hand over all the data behind the groundwater study, threatening to fine the company $25,000 each day until it does. If AES refuses, the board said it may order the company tocease and desist” operations. But AES provides 17 percent of the island’s electricity. Does the government stop a coal company from polluting the water, or cut off power to thousands of homes? The people of Puerto Rico lose either way.