FILE - In this Oct. 28, 2009, file photo, empty water tanks sit at the edge of a brine well operation, shown at right of tanks, as a major irrigation canal flows by in Carlsbad, N.M. Almost half of Carlsbad school bus routes travel over the well, on a busy road that borders a giant, underground cavern that resulted from years of manufacturing brine for the oil and gas industry. It's been nearly nine years since state officials first sounded the alarm about a potential collapse, but experts say could happen at any time. (AP Photo/Susan Montoya Bryan, File)