(AP) - A preliminary report says the oil pipeline explosion in Minnesota that killed two men from Superior was caused, in part, by improper procedures used during repair work.
U.S. Pipeline Safety Office spokesman Damon Hill says the investigation is still ongoing, but it looks like there were improper procedures conducted.
Hill says the exact cause of the explosion won't be known until the investigation is finished.
He says Enbridge has been ordered to make changes, such as operating under a reduced rate of pressure until the exact cause is known.
The pipeline from Canada that feeds oil to the U.S. caught fire near Clearbrook, Minnesota last November while two workers were doing repairs. Dave Mussati Jr. and Steve Arnovich were killed. They were contract workers from Enbridge's office in Superior.
(Copyright 2008 by The Associated Press. All Rights Reserved.)