Chromium is a naturally occurring heavy metal that is commonly used in industrial processes and can cause severe health effects in humans. Although it can be released through natural forces, the majority of the environmental releases of chromium are from industrial sources. The industries with the largest contribution to chromium levels include leather tanning operations, metal processing, stainless steel welding, chromate production, and chrome pigment production. Chromium can be found in many consumer products, including wood treated with copper dichromate, leather tanned with chromic sulfate, and stainless steel cookware. 
Of the chromium sites identified so far by Blacksmith Institute, roughly 75% are located in South Asia. Of these, nearly a third are associated with tannery operations, with mining and metallurgy sites also contributing significantly. The high concentration of chromium sites in South Asia is primarily due to the abundance of tanneries in the region. Many of the tanneries have poor environmental controls.