Frequent Questions

11. Chromium-6 Study Update

 EPA is actively working on the development of an updated Integrated Risk Information System (IRIS) assessment of hexavalent chromium (chromium-6), which will include a comprehensive evaluation of potential health effects associated with oral exposure to hexavalent chromium. EPA has not released a schedule for the completion of the assessment.
 
Once EPA completes its assessment the Office of Water will evaluate the findings to determine if revisions to the Drinking Water for Chromium are warranted.
 
The agency has also collected nationally representative data on the occurrence of both total chromium and hexavalent chromium through the third Unregulated Contaminant Monitoring Rule (UCMR3). Only one of the almost 5,000 public water systems that monitored total chromium under the UCMR3 reported results that exceeded EPA’s standard.  
 
EPA has a drinking water standard of 100 parts per billion (ppb) for total chromium. This includes all forms of chromium, including hexavalent chromium. EPA and states are responsible for ensuring that public water systems are in compliance with the current standard for total chromium. 
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