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 This website is no longer updated and links to external websites and some internal pages may not work.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 »

Visibility and Haze

EPA Finalizes Emissions Trading Program Helping State and Tribal Governments Improve Visibility in National Parks and Wilderness Areas

On October, 5, 2006, EPA finalized an alternative emissions trading program that gives flexibility for states or tribal governments in ways to apply Best Alternative Retrofit Technology (BART). The BART requirements would be satisfied if the trading program meets or exceeds the visibility benefits resulting from BART.

  • Rule (PDF) (24 pp, 331 K) - Federal Register, Oct 13, 2006
You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.