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.

EPA email security infrastructure (RSS)

Urgent: The EPA has recently taken steps to enhance its email security infrastructure to better protect the EPA against potentially malicious sources (spam email and spoofed messages). Emails sent to the EPA from an email system that cannot be verified are tagged with a warning label, and the receiver of the email will be asked to determine if it was sent from a known legitimate source. If you send an email to the EPA, and it is tagged with such a warning label, you will be asked to make a change to the email servers at your organization so that future emails are not rejected.

The specific sender validations are named “SPF” and “DMARC”. These are described in the following Wikipedia  articles:

Important: Between now and September 30, 2018, messages that do not pass these tests will be delivered, but tagged to the recipient with a warning. After October, 2018, they will no longer be delivered.