**ADVANCE FOR WEEKEND AUG. 11-12 ** A caribou grazes near oil transit lines running across the tundra on Alaska's North Slope, Aug. 5, 2006. A series of leaks caused BP to shut down the oil fields in 2006. An upcoming state study shows that all kinds of spills, from crude to gasoline to tainted water, have occurred with regularity over the last decade on the remote wetlands of the Arctic tundra. (AP Photo/Al Grillo)