SALT LAKE CITY -- Federal regulators say testing Chevron Corp. conducted after a June pipeline leak was the apparent cause of a second oil spill in Salt Lake City a week ago.
Pipeline regulators at the U.S. Department of Transportation say Chevron failed to purge the pipeline of water used for a pressure test after June's spill of about 800 barrels of crude oil.
Some of the water collected inside a shut-off valve that split open Dec. 1 during a hard freeze, leaking an estimated 500 barrels of oil.
The Associated Press obtained a copy of a 10-page order the Pipeline and Hazardous Materials Safety Administration issued Chevron on Wednesday.
In the order, regulators call the troubled pipeline a "serious" threat and ordered Chevron to take a dozen steps before seeking approval to operate it again.