FAIRBANKS — Officials at Flint Hills Resources are unsure what caused a containment field surrounding an already empty oil tank to fill with roughly 1,800 gallons of crude oil at the North Pole refinery earlier this week, but they think a faulty valve may be responsible.
Flint Hills spokesperson Jeff Cook said the oil likely came from a piping system — used primarily to collect waste fluids — that connects the oil tanks and their surrounding containment fields. This same piping system is sometimes used to move crude oil when the situation calls for it, Cook said.
“It’s not all a waste system. It’s a recycling system, and sometimes we’re putting it back. It just depends on what we’re doing that day and the operation — are we doing maintenance, are we switching from one tank to another, and are we recirculating crude? It’s not routine, but it’s certainly not uncommon,” Cook said.
The spill was discovered by a refinery worker during a routine inspection Sunday. According to a situation report issued by the Alaska Department of Environmental Conservation Thursday, a suspected sump system valve — which was closed when the incident occurred — is being examined to determine if crude oil back-flowed into the containment area from the system piping.
Refinery workers used the sump system to remove the liquid crude, and contaminated ice and snow was collected and flushed into the wastewater treatment system, according to the report.
Paul Lhotka, field on-scene coordinator for the department, said the initial response is complete and there was no contamination of the ground water, but more work remains to be done in the future.
“There’s going to be some contaminated soil remaining. The containment is constructed of soil overlying (impermeable) fabric, and those contaminated soils or gravel will come out after breakup,” Lhotka said.
Flint Hills contracts with several approved waste-disposal facilities, one of which will process the contaminated soils this spring, according to Cook.
Contact Dorothy Chomicz at 459-7590.