Despite widespread concern about potential human health impacts from hydraulic fracturing, the lifetime toxic chemical releases associated with coal-generated electricity are 10 to 100 times greater than those from electricity generated with natural gas obtained via fracking, according to a new University of Michigan study.

The study is a comparative analysis of the harmful health effects of electricity produced from shale gas and coal. It looks at the amount of toxic chemicals released into the air, soil and water during both the resource extraction and electricity generation phases of both technologies and concludes that the potential human health impacts of electricity from coal are much higher. The findings suggest that as the U.S. energy market continues to shift from coal to natural gas, the overall "toxicity burden" of the electricity sector will decrease, said study corresponding author Shelie Miller, an environmental engineer and an associate professor at the U-M School for Environment and Sustainability's Center for Sustainable Systems. 

The findings suggest that as the U.S. energy market continues to shift from coal to natural gas, the overall "toxicity burden" of the electricity sector will decrease, said study corresponding author Shelie Miller, an environmental engineer and an associate professor at the U-M School for Environment and Sustainability's Center for Sustainable Systems.

"This analysis does not imply that concerns associated with shale gas production are unfounded, only that the overall toxic load of coal is definitely greater," Miller said. "And while the study doesn't address this directly, we should be pursuing renewables more aggressively if we really want to decrease the human toxicity burden of our energy system." Read more.