As if terrorist attacks weren’t enough of a threat, unexploded munitions at 16,000 inactive military ranges in the United States present “imminent and substantial” public health risks, according to newly released U.S. EPA documents. The agency said the problem might require the largest environmental cleanup program ever implemented by the feds. Jeff Ruch, director of Public Employees for Environmental Responsibility, said his organization obtained the documents confidentially from an EPA whistleblower who believes that the munitions — including chemical and biological weapons — could be leaking into soil and groundwater. The weapons are spread across 30 million to 40 million acres nationwide, an area about the size of Florida.