Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

JavaScript appears to be disabled on this computer. Please click here to see any active alerts.

Contact Us About Web Policies and Procedures

Please use the form below to send us comments or questions about EPA Web Policies and standards. If you send comments about other things here, it's forwarded to EPA's general mailbox. Be sure to include your e-mail address if you’d like a response.

Or, write to us at:

US EPA, Headquarters and Chemical Library
1200 Pennsylvania Ave. NW, MC3404T
Washington DC 20460