Supplies still aren’t reaching where they’re needed in Puerto Rico, and some people who desperately need water are getting it from hazardous sources. After evaluating five places deemed especially hazardous to health and the environment, so-called Superfund sites, Environmental Protection Agency staff saw people accessing wells at a chemical-tainted water source on the northern coast of Puerto Rico.

“We have confirmed that residents accessed wells only at the Dorado site,” an EPA spokesperson told The Verge in an email. The contaminated wells in Dorado are part of two water systems that together supply water to more than 67,000 people. Industrial solvents have been tainting portions of this system since the 1980s, according to an EPA report, resulting in permanent and temporary closures of some of the wells. When the site was officially added to the Superfund list in September 2016, the EPA had not identified the source of the contamination.

Puerto Rico has been experiencing a dangerous water shortage since Hurricane Maria made landfall over three weeks ago. More than a third of the 3.4 million US citizens on the island still can’t turn on the tap to get clean water, and reports say that emergency water supplies aren’t reaching people who need them. “The lack of water is far worse than anything experienced in Florida and Texas after Hurricanes Irma and Harvey,” the New York Times reported on Thursday.

The Environmental Protection Agency received reports that people were trying to access water at toxic Superfund sites, according to a news release issued on Wednesday. These sites are at Caguas, San German, and Dorado, an agency spokesperson clarified in an email. The EPA advised people against tampering with or drinking from sealed and locked wells. But without access to safe water, people are forced to make the terrible choice of drinking from a risky source, or nothing at all.

The agency investigated the three sites that were reported, plus two additional ones in Cabo Rojo and Maunabo, an EPA spokesperson said. Although they’re scattered across the island, all are groundwater sources contaminated with industrial solvents used for metal degreasing and dry cleaning. Exposure to these solvents can have dangerous health effects, such as harming the liver and increasing cancer risk. But, dehydration is dangerous too.

The EPA doesn’t know how many people accessed the water in Dorado, but intends to take samples and to secure all of the sites it evaluated, the spokesperson said. Of course, that doesn’t change the fact that people desperately need water. The EPA says that the Federal Emergency Management Agency has brought in a water truck to supply people in the community, and that power to the water treatment plant should turn back on today — more than three weeks after Hurricane Maria struck.