Coal involves burning tons of minerals, concentrating the non-carbon elements of those minerals into coal ash and exhaust. A lot of those other minerals are radioactive or otherwise toxic.<p><a href="http:&#x2F;&#x2F;www.scientificamerican.com&#x2F;article&#x2F;coal-ash-is-more-radioactive-than-nuclear-waste&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.scientificamerican.com&#x2F;article&#x2F;coal-ash-is-more-r...</a><p>However, to make a fair comparison you should also consider the toxic byproducts of uranium extraction and purification. Coal is not refined in anywhere near the same degree as reactor-grade uranium.