plaster of Paris
<p >The chemical reaction that occurs when plaster is mixed with water is <a href="http://en.wikipedia.org/wiki/Exothermic" title="Exothermic" >exothermic</a> in nature and can therefore cause severe burns. The potential dangers were demonstrated in January 2007, when a sixteen-year-old girl suffered <a href="http://en.wikipedia.org/wiki/Third-degree_burn" title="Third-degree burn" class="mw-redirect" >third-degree burns</a> after encasing her hands in a bucket of plaster as part of a <a href="http://en.wikipedia.org/wiki/School" title="School" >school</a> <a href="http://en.wikipedia.org/wiki/Art" title="Art" >art</a> project in <a href="http://en.wikipedia.org/wiki/Lincolnshire" title="Lincolnshire" >Lincolnshire</a>, England. The burns were so severe that she subsequently had both thumbs and six of her fingers <a href="http://en.wikipedia.org/wiki/Amputate" title="Amputate" class="mw-redirect" >amputated</a>.<sup id="cite_ref-4" class="reference" ><a href="http://en.wikipedia.org/wiki/Plaster_of_Paris#cite_note-4" >[5]</a></sup><sup id="cite_ref-5" class="reference" ><a href="http://en.wikipedia.org/wiki/Plaster_of_Paris#cite_note-5" >[6]</a></sup><sup id="cite_ref-6" class="reference" ><a href="http://en.wikipedia.org/wiki/Plaster_of_Paris#cite_note-6" >[7]</a></sup> For this reason only thin layers of plaster should be used, with time to cool between layers, or strips of cloth in plaster laid-up in the method used by the medical field. In place of plaster, <a href="http://en.wikipedia.org/wiki/Alginate" title="Alginate" class="mw-redirect" >alginate</a> can safely be used for casting body parts.</p>
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Some variations of plaster that contain powdered <a href="http://en.wikipedia.org/wiki/Silica" title="Silica" class="mw-redirect" >silica</a> or <a href="http://en.wikipedia.org/wiki/Asbestos" title="Asbestos" >asbestos</a> may present
health hazards if inhaled. Asbestos is a known <a href="http://en.wikipedia.org/wiki/Irritation" title="Irritation" >irritant</a> when inhaled in powder form can cause cancer, especially in people who smoke, and inhalation can also cause <a href="http://en.wikipedia.org/wiki/Asbestosis" title="Asbestosis" >asbestosis</a>. Inhaled silica can cause <a href="http://en.wikipedia.org/wiki/Silicosis" title="Silicosis" >silicosis</a> and (in very rare cases) can encourage the development of <a href="http://en.wikipedia.org/wiki/Cancer" title="Cancer" >cancer</a>. Persons working regularly with plaster containing these additives should take precautions to avoid inhaling powdered plaster, cured or uncured. (Note that asbestos is rarely used in modern plaster formulations because of its carcinogenic<sup id="cite_ref-7" class="reference" ><a href="http://en.wikipedia.org/wiki/Plaster_of_Paris#cite_note-7" >[8]</a></sup> effects.)</p>