An estimated 17.6 million Americans live within one mile of an active oil or gas well, according to a study published today (August 23), in Environmental Health Perspectives, a peer-reviewed journal published by the National Institute of Environmental Health Sciences. The study, by researchers at PSE Healthy Energy, a nonprofit research institute; the University of California, Berkeley; and Harvey Mudd College, is the first peer-reviewed nationwide measurement of the number of people living in close proximity to actively producing oil and gas wells.