It took decades for the stand of hardwood trees near Lake Texoma to grow tall. It took less than a day for 3,000 gallons of drilling wastewater to destroy them. The salty fluid spilled from aging oil field pipes in February 2012 in the Hagerman National Wildlife Refuge north of Dallas. But you won't find the details of the spill in the records of the Texas Railroad Commission, the state agency in charge of regulating the state's oil and gas industry.