DENVER (AP) – The mustard-colored muck that spilled from a Colorado mine and surged into a river contains heavy metals including lead and arsenic, federal environmental officials confirmed Friday, but they didn’t immediately discuss amounts in the water or health risks.

The spill also contained cadmium, aluminum, copper and calcium, the Environmental Protection Agency said. During a public meeting in Durango, EPA Regional Director Shaun McGrath did not mention whether the elements posed a health hazard but said local authorities were right to close the Animas River to human activities.

At least two of the heavy metals can be lethal for humans in long-term exposure. Arsenic at high levels can cause blindness, paralysis and cancer. Lead poisoning can create muscle and vision problems for adults, harm development in fetuses, and lead to kidney disease, developmental problems and sometimes death in children, the agency said.