A little-known program under federal environment law is being used to permit oil and gas companies to inject waste into the state’s aquifers, even as the thirst for groundwater grows. … California is one of at least 23 states where so-called aquifer exemptions — exceptions to federal environmental law that allow mining or oil and gas companies to dump waste directly into drinking water reserves — have been issued. … Exemptions are granted by a U.S. Environmental Protection Agency division that has had difficulties in recordkeeping and has been criticized for its controversial management of groundwater reserves. A 2012 ProPublica investigation disclosed that the federal government had given energy and mining companies permission to pollute U.S. aquifers in more than 1,000 locations, as part of an underground disposal program that allows toxic substances to be disposed of in nearly 700,000 waste wells across the country. … In many cases, the exact locations of the exemptions and the precise boundaries of areas where aquifer pollution was allowed had been left poorly defined, raising concerns that waste might reach adjacent drinking water. Several states, including California, have since admitted they’ve allowed that to happen. … The federal Safe Drinking Water Act distinguishes between underground aquifers that are too salty or dirty to ever be used and those that are pure enough to drink from, defining the latter as an “underground source of drinking water.” … Applications to exempt an aquifer are supposed to undergo extensive scientific scrutiny, and today they usually do. But when the Safe Drinking Water Act was initially implemented, the federal government traded away much of that scrutiny as a compromise to win state and industry support for the new regulations. … Despite the substantial wiggle room granted by law, California has come under fire for not managing its roughly 52,000 waste wells properly. In 2011, the EPA sharply criticized the state for keeping poor records, mismanaging its environmental reviews, and failing to follow federal law. It suggested that the state’s autonomy over its groundwater regulations could be revoked, and that the EPA would impose federal oversight.
To fend off that change, California launched its own review and, in 2014, began to uncover extraordinary lapses: Thanks to poor recordkeeping and confusion over which aquifers had been written off, the state found more than 2,000 wells were injecting toxins not into exempt areas, but directly into the state’s drinking water aquifers. … Those 11 aquifers have been the focus of much of the state’s renewed attention, but California still hasn’t confirmed the borders of the hundreds of legacy exemptions in other aquifers that date back to the 1980s. … In our 2012 investigation, ProPublica found numerous cases in which waste defied the containment that regulators and their computer models had promised, and contamination spread.