A frozen valve is blamed in the spill early Wednesday of 300 to 400 barrels of an oil and water mixture from the Phillips 66 refinery in Woods Cross.

Refinery administrative manager Mark Kendall said most of the spill was confined to a compound around the storm drain holding tanks but some of the mixture went into a drainage ditch and ran out of the refinery's west side.The leak occurred between 1 a.m. and 8 a.m. Wednesday, Kendall said. The line was secure during a plant inspection at 1 a.m. but found leaking in an 8 a.m. inspection, he said.

Kendall said cleanup crews were called in and had the leak halted by 9 a.m. and are now cleaning up the residue from the drainage ditch and private property downstream.

While estimating the leak at 300 to 400 barrels, Kendall said it is difficult to estimate how much stayed in the holding pond and how much actually leaked out of the refinery grounds. The heavy, deep snow acted like a sponge and soaked up much of the oil and water, he said.

The cold weather that froze the valve is also hampering the cleanup effort, he said. The vacuum hoses being used to suck up the oil and water are freezing, slowing the cleanup process, he said.

Kendall said a cleanup that normally would take a few hours is stretching into several days, but the oil mixture has been contained and is not going any farther down the creek.

A plant supervisor walked the creek along the half-mile length of the spill, he said, and reported finding no birds or other wildlife affected. One of the downstream property owners has some domestic ducks near the creek, Kendall said, which may account for the dead birds reported by television news crews.

Kendall said the refinery has its own sewage and storm-water drainage system on site. Because of the petroleum products refined at the plant, it does not dump its sewage or runoff water into the city's system.

The runoff, along with water drained from the refinery's petroleum tanks, is pumped into the storm drain holding tanks for reprocessing to remove the petroleum products, Kendall said.

It was that mix of water, crude oil, and gasoline that leaked from the line when a strainer, designed to keep trash out of the line's pump, froze and sprang a leak, he said.

Kendall said the refinery notified the federal Environmental Protection Agency and the Davis County Health Department's environmental health division about the incident and is working with both agencies.

The spill is being cleaned up by recovery crews using vacuum hoses and tank trucks, Kendall said, and will be returned to the refinery for reprocessing. And, he said, the refinery is working with the property owners downstream to restore their land.