Colorado's Animas River turns yellow with pollution
10 August 2015 Last updated at 22:42 BST
The US Environmental Protection Agency (EPA) says it now estimates that a leak that turned a Colorado river yellow has caused three times as much pollution as initially thought.
The Animas River has been closed since five EPA workers accidentally sent contaminated water pouring downstream.
The pollution includes lead, cadmium and arsenic.
More than 1,000 wells may have been affected by yellow water stretching over 100 miles (160km) into neighbouring New Mexico.
Produced by Andrew Webb.