An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Radiation Protection

Subpart W Rulemaking Activity: Documents

NESHAP Subpart W is a radon emission standard for operating uranium mill tailings. In accordance with the Clean Air Act Amendments of 1990, EPA formed a workgroup to review the standard. On May 2, 2014, EPA issued a Notice of Proposed Rulemaking with proposed revisions to Subpart W. On January 17, 2017, EPA officially issued a final rule that revised that updated Subpart W. View the final rule in the Federal Register. Note: The effective date of this action has been deferred to March 21, 2017.

Supporting documents are available below in chronological order, from most recent to oldest:

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.