A few days ago, environmental scientists and representatives of the Environmental Protection Agency trudged through steaming toxic sludge at what the federal agency considers one of the worst Superfund sites in California. Iron Mountain, a former mine that is dripping with acid capable of eating away even specially resistant concrete, is outside Redding.
The mine shut down in the 1960s and has been closed to the public since.
But runoff from the site potentially threatens salmon in the Sacramento River, which is why the EPA closely watches a treatment facility that has kept the river clean and has kept pollution mostly at the mine, said Rick Sugarek, an EPA point person for a cleanup effort that has spanned more than 20 years.
About 2 percent of the original pollution continues to discharge from the mine, said Sugarek. And that's unlikely to change because there's simply no technology to get rid of it. The San Francisco Chronicle explains why that is, and how Iron Mountain became a hazard.
"This is a common problem at hard rock and coal mines - iron sulfide turns into sulfuric acid - but at Iron Mountain, it's 500 times more concentrated. It's more like battery acid coming out of the mountain," he told CNN.
The EPA spends $1 million a year on lime alone to help neutralize the acid, he said.
There are several dozen workers and contractors who do maintainence for the EPA on the plant. Even with stringent safety measures in place, workers have reported going home and their jeans falling apart, said Sugarek.