A closed gold mine in Colorado has been spilling yellow sludge into the Animas River since Wednesday, with the spoils now reaching New Mexico, according to an official cited by the Associated Press. The sludge made its way to the communities of Aztec Friday night and Farmington Saturday morning, with officials shutting down the river’s access to water-treatment plants in both places, AP reported.

The sludge originated at the Gold King Mine, with an estimated 1 million gallons beginning to spill into the Animas River after a U.S. Environmental Protection Agency (EPA) crew accidentally breached a debris dam inside the mine, which has been inactive since 1923.

Mine wastewater is apparently getting close to Utah. EPA officials confirmed it contains heavy metals, including arsenic and lead, the New York Times reported.

While the concentrations are not yet known, the EPA released acidity test results Saturday, saying the water near the spill had a pH level of 3.74, which it described as similar to the acidity of apples and tomato juice, AP reported.

The EPA has issued a warning for people to stay out of the river and ensure that domestic animals do not drink from it.

Joan Card, an adviser to EPA Regional Director Shaun McGrath, indicated Saturday that water continues to spill from the mine at a rate of about 700 gallons per minute, AP said.