Outdoor enthusiasts in Utah were urged Wednesday to use caution along a river tainted by a toxic waste spill at an abandoned gold mine in Colorado a week ago.
The Utah Department of Environmental Quality said the health effects of the orange-tinted spill that has entered the San Juan River remain unknown.
"People are warned to stay out of any colored sediment, but if exposed are encouraged to wash it off," it said in a statement.
"Also, recreationalists shouldn't drink even filtered water directly from the river, but instead drink and cook with potable water that has been brought in."
Drinking water in Utah has not been affected, the department added.
Three million gallons (11.4 million liters) of toxic waste spilled into the Animas River last Wednesday in a botched clean-up operation overseen by the Environmental Protection Agency (EPA).
The dramatic plume, dozens of miles (kilometers) long, made its way downriver to New Mexico, where the Animas enters the San Juan, a tributary of the Colorado River.
Losing its vivid color as it becomes more diluted, it could still harbor a high level of toxic substances such as lead and arsenic, experts say.
The spill prompted states of emergency to be declared in Colorado, New Mexico and the vast Navajo Nation reservation that straddles state lines.
© 2015 AFP