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 This website is no longer updated and links to external websites and some internal pages may not work.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

Emissions Trading Could Satisfy Best Available Retrofit Technology Requirements Under EPAs Regional Haze Program

On July 20, 2005, EPA proposed a new regulation that would give states the option to develop an emissions trading program to improve visibility in national parks and wilderness areas. EPA’s proposal outlines the process that a state or tribal governments would use to show that an emissions trading program could be used to meet the Clean Air Visibility Rule’s Best Available Retrofit Technology or BART Requirements. EPA will accept comments on the proposed rule for 45 days after it is published in the Federal Register.

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