The northeastern corner of the US state of Oklahoma was once the most productive lead and zinc mining areas of the world. The metals were discovered here in 1914, just in time for the increased demands for ammunitions created by the First World War. Soon there were hundreds of mines and thousands of people toiled under the ground working for the Picher Lead Company. The town of Picher, along with the nearby towns of Cardin and Treece in Kansas developed overnight.

At its peak, Picher’ mills processed nearly 5,000 tons of raw ore a day. They crushed the ore into fine grains and melted it in giant smelter to filter away the impurities. Only a fraction of the melted ore produced actual valuable minerals. The useless residue, contaminated with toxic metals, were piled up outside the mines until it created a 7,000-acre ridge containing 70 million tons of mine tailings, and 36 million tons of mill sand and sludge. This fine-grained mine tailings known as chat, blew all over the town and people breathed them in. When it rained, the runoff from the chat piles got into the local water supply.

The main street of Picher. Some shops still have items displayed at the windows. Photo credit: Jeremy/Flickr