An official website of the United States government.

Due to a lapse in appropriations, EPA websites will not be regularly updated. In the event of an environmental emergency imminently threatening the safety of human life or where necessary to protect certain property, the EPA website will be updated with appropriate information. Please note that all information on the EPA website may not be up to date, and transactions and inquiries submitted to the EPA website may not be processed or responded to until appropriations are enacted.

We've made some changes to If the information you are looking for is not here, you may be able to find it on the EPA Web Archive or the January 19, 2017 Web Snapshot.


Contact Us about Radon

Report an environmental violation

Report possible violations of environmental laws and regulations.

Center for Radon and Air Toxics:

Regular Mail Address: Courier Service or Delivery address:
U.S. EPA/Office of Radiation and Indoor Air
Indoor Environments Division
1200 Pennsylvania Avenue, NW
Mail Code 6609T
Washington, DC 20460
U.S. EPA/Office of Radiation and Indoor Air
Indoor Environments Division
1301 Constitution Avenue, NW
MC 6609T
Washington, DC  20004

Search Frequently Asked Questions

In addition to questions and answers relating to indoor environments, you may use this database to find information on any of our topic areas, for example, Asthma, Radon, Mold and Moisture, Smoke-free Homes, IAQ Design Tools for Schools, Indoor airPLUS and General Indoor Air Quality Issues.

You may also use this link to subscribe to any new information or updated information relating to any of the topics that may be posted on our website. 

Still can't find the answer?  Ask a question.