Today the most radioactive emissions into our environment are from coal fired power stations, both up the chimney and in the ash, see <a href="http://www.scientificamerican.com/article.cfm?id=coal-ash-is-more-radioactive-than-nuclear-waste;">http://www.scientificamerican.com/article.cfm?id=coal-ash-is-more-radioactive-than-nuclear-waste;</a> and some coal ash is used in cement manufacture.