EDMONTON, Alberta, May 7 (UPI) -- Alberta's worst oil spill in 30 years probably was caused by poorly compacted soil under the pipeline and an ill-fitted weld, the pipeline operator says.
The April 29 break in the Rainbow pipeline near Peace River gushed at least 28,000 barrels of crude, Plains Midstream Canada told the Edmonton Journal Friday.
"It appears that the soil beneath the pipeline was inadequately compacted, resulting in stress," said company Vice President Stephen Bart.
He said the pipeline had been shut down and restarted several times over "unstable conditions" just before the leak was detected, but seemed to be sound.
Plains Midstream has been criticized for not releasing details of the spill immediately, and executives in Alberta did not speak publicly until Friday, a week later.
Residents of the Lubicon First Nations in Little Buffalo, about 20 miles away, have been complaining of headaches and nausea, and seven beavers and many waterfowl have died.
The pipeline moves about 187,000 barrels daily from Zama to Edmonton.
Plains Midstream is a subsidiary of Plains All American Pipeline, based in Houston.
