Changes

<p>In 1962, <a title="Houghton Mifflin" href="http://en.wikipedia.org/wiki/Houghton_Mifflin">Houghton Mifflin</a> published <em><a title="Silent Spring" href="http://en.wikipedia.org/wiki/Silent_Spring">Silent Spring</a></em> by American biologist <a title="Rachel Carson" href="http://en.wikipedia.org/wiki/Rachel_Carson">Rachel Carson</a>. The book catalogued the environmental impacts of the indiscriminate spraying of DDT in the US and questioned the logic of releasing large amounts of chemicals into the environment without fully understanding their effects on ecology or human health. The book suggested that DDT and other pesticides may cause <a title="Cancer" href="http://en.wikipedia.org/wiki/Cancer">cancer</a> and that their agricultural use was a threat to wildlife, particularly birds.<sup class="reference" id="_ref-Silent_Spring_0"><a title="" href="http://en.wikipedia.org/wiki/DDT#_note-Silent_Spring">[3]</a></sup> The book resulted in a large public outcry that eventually led to DDT being banned in the US, and its publication was one of the signature events in the birth of the <a title="Environmentalism" href="http://en.wikipedia.org/wiki/Environmentalism">environmental movement</a>. DDT was subsequently banned for agricultural use worldwide, but its limited use in <a title="Vector (biology)" href="http://en.wikipedia.org/wiki/Vector_%28biology%29">disease vector</a> control continues to this day in certain parts of the world and remains controversial.</p>

<p>Along with the passage of the <a title="Endangered Species Act" href="http://en.wikipedia.org/wiki/Endangered_Species_Act">Endangered Species Act</a>, the US ban on DDT is cited by scientists as a major factor in the comeback of the <a title="Bald eagle" href="http://en.wikipedia.org/wiki/Bald_eagle">bald eagle</a> in the contiguous US.<sup class="reference" id="_ref-1"><a title="" href="http://en.wikipedia.org/wiki/DDT#_note-1">[4]</a></sup></p>

<p><a id="Properties_and_chemistry" name="Properties_and_chemistry"></a></p>

<h2><span class="editsection"></span><span class="mw-headline">Properties and chemistry</span></h2>