President Lyndon B. Johnson signing the 1967 Clean Air Act in the East Room of the White House.
Mike Geissinger
LBJ :: Online Photo Archive Search, who explicitly state that the photos are in the public domain: <a rel="nofollow" class="external free" href="http://www.lbjlibrary.org/collections/photo-archive.html">http://www.lbjlibrary.org/collections/photo-archive.html</a> (search C7607-7, the serial number corresponding to this image)