The <a href="https://en.wikipedia.org/wiki/United_States_Department_of_Energy" id="mwARo" rel="mw:WikiLink" title="United States Department of Energy">U.S. Department of Energy</a> declassifies documents showing world's largest <a href="https://en.wikipedia.org/wiki/Mercury_(element)" id="mwARs" rel="mw:WikiLink" title="Mercury (element)">mercury</a> pollution event in <a href="https://en.wikipedia.org/wiki/Oak_Ridge,_Tennessee" id="mwARw" rel="mw:WikiLink" title="Oak Ridge, Tennessee">Oak Ridge, Tennessee</a> (ultimately found to be <span about="#mwt62" data-mw='{"parts":[{"template":{"target":{"wt":"convert","href":"./Template:Convert"},"params":{"1":{"wt":"4.2"},"2":{"wt":"e6lb"},"disp":{"wt":"sqbr"}},"i":0}}]}' id="mwAR0" typeof="mw:Transclusion">4.2</span><span about="#mwt62" typeof="mw:Entity"> </span><span about="#mwt62">million pounds [1.9</span><span about="#mwt62" typeof="mw:Entity"> </span><span about="#mwt62">kt]</span>), in response to the <i id="mwAR4">Appalachian Observer'</i>s <a href="https://en.wikipedia.org/wiki/Freedom_of_Information_Act_(United_States)" id="mwAR8" rel="mw:WikiLink" title="Freedom of Information Act (United States)">Freedom of Information Act</a> request.