Hexavalent chromium is a toxic industrial pollutant from metal plating and wood treatment. It enters water via industrial discharge and causes cancer when ingested.

Hexavalent chromium, also known as chromium-6, is primarily released into the environment through industrial processes. Beyond metal plating and wood treatment, it's used in leather tanning and textile manufacturing. It contaminates water through improper disposal and leaching from industrial sites. Measured in parts per billion (ppb), its presence in drinking water became widely known after the Hinkley, California case popularized by Erin Brockovich. The EPA monitors total chromium levels, but some states have implemented stricter standards specifically for the hexavalent form due to its toxicity.