Epstein et al. (2011) externalities increase the true cost of coal several times over Skeptical Science Skeptical Science previous examined public safety ignoring externalities not the actual net cost impact of burning fossil fuels on public health article The True Cost of Coal Power public safety "The True Cost of Coal Power" The True Cost of Coal Power public safety costs of externalities Epstein et al. (2011) public safety Epstein (2011) Skeptical Science previous examined Skeptical Science: public safety externalities Epstein (2011) externalities http://www.skepticalscience.com/true-cost-of-coal-power.html