America’s Deadliest Lake is Loaded with Toxic Chemicals


From afar, at just the right angle, the surface of this deceptively peaceful-looking body of water reflects the sky, making it look like a clear, soothing blue. But Berkeley Pit, known as 'America's deadliest lake,' isn't actually a lake at all – it's the remains of an open-pit mine full of over 40 billion gallons of acidic water and extremely toxic chemicals. 

The mile-long, half-mile-wide pit is one of the country's largest Superfund sites, and one of very few that's not only accessible to the public, but a tourist attraction. Pay a two dollar admission fee and you can climb up to a viewing platform to see the pit full of dissolved heavy metals like copper, arsenic, cadmium, zinc and sulfuric acid. There's even a gift shop.

Berkeley Pit 3

Established in 1955 in Butte, Montana, the copper mine operated continuously for decades, but in 1995, a flock of migratory snow geese that landed in the lake and got stuck there due to stormy weather. By the time the storm passed, 342 of the geese were dead, prompting an investigation into the toxicity of the pit. The pit water actually corroded the birds' esophagi. There's now a 24-hour bird watch program to make sure that it doesn't happen again.

Berkeley Pit 4

But even more alarming than that is the fact that the water level in the pit is constantly rising. If it reaches critical levels, it could contaminate the ground water of the Butte valley, which is inhabited by over 30,000 people. To make sure that doesn't happen, a water treatment plant was built to pump and treat the pit water for use in nearby mining operations. Read more about Berkeley Pit at