<a href="https://en.wikipedia.org/wiki/1948_Donora_smog" id="mwhA" rel="mw:WikiLink" title="1948 Donora smog">Ecological disaster</a> in <a href="https://en.wikipedia.org/wiki/Donora,_Pennsylvania" id="mwhQ" rel="mw:WikiLink" title="Donora, Pennsylvania">Donora, Pennsylvania</a>.<sup about="#mwt30" class="mw-ref reference" data-mw='{"name":"ref","attrs":{},"body":{"id":"mw-reference-text-cite_note-4"}}' id="cite_ref-4" rel="dc:references" typeof="mw:Extension/ref"><a href="./October_27#cite_note-4" id="mwhg" style="counter-reset: mw-Ref 4;"><span class="mw-reflink-text" id="mwhw">[4]</span></a></sup>
<span class="mw-reference-text" id="mw-reference-text-cite_note-4"><cite about="#mwt27" class="citation news cs1" id="CITEREFHamill,_Sean_D.2008">Hamill, Sean D. (November 1, 2008). <a class="external text" href="https://www.nytimes.com/2008/11/02/us/02smog.html" id="mwBt0" rel="mw:ExtLink nofollow">"Unveiling a Museum, a Pennsylvania Town Remembers the Smog That Killed 20"</a>. <i id="mwBt4"><a href="./The_New_York_Times" id="mwBt8" rel="mw:WikiLink" title="The New York Times">The New York Times</a></i><span class="reference-accessdate" id="mwBuA">. Retrieved <span class="nowrap" id="mwBuE">November 2,</span> 2008</span>.</cite><span about="#mwt27" class="Z3988" id="mwBuI" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.jtitle=The+New+York+Times&amp;rft.atitle=Unveiling+a+Museum%2C+a+Pennsylvania+Town+Remembers+the+Smog+That+Killed+20&amp;rft.date=2008-11-01&amp;rft.au=Hamill%2C+Sean+D.&amp;rft_id=https%3A%2F%2Fwww.nytimes.com%2F2008%2F11%2F02%2Fus%2F02smog.html&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AOctober+27"></span></span>