TATUM, N.M. -- In places like Tatum, where groundwater is near the surface, oil and gas drillers can't use pits for waste or drill cuttings and must use steel tanks as part of a "closed loop" system. But those strict requirements will likely end soon. Bucking a national trend toward tightening rules, New Mexico oil and gas officials are de-fanging the pit rule at the request of the oil and gas industry. Environmental groups and ranchers are fighting to keep New Mexico's pit rule intact, saying tanks and closed-loop systems have kept drilling wastes out of soils and groundwater. It is a fight they expect to lose.