WILLARD -- A pipeline that leaked at least 20,000 gallons of diesel fuel near Willard Bay failed a federally mandated pressure test Monday.
The test was ordered by the Pipeline and Hazardous Materials Safety Administration. The pipeline is owned by Chevron Pipe Line Co.
To pass, the pipeline is required to hold 2,600 pounds per square inch of water for 30 minutes, said John Whitehead, assistant director of the Utah Division of Water Quality.
However, when that amount of pressure was applied Monday, the pipeline failed after six minutes.
Workers were expected to excavate and clean the pipe Tuesday in preparation for another test, Whitehead said.
The cause of the test failure is being investigated, Gareth Johnstone, a spokesman for Chevron, said in an email. The pipeline's normal operating pressure is 1,870 psi, he added.
The leak was discovered March 18 following a seam rupture, near Willard Bay, to the 8-inch pipeline that extends from Salt Lake City to Burley, Idaho.
Trace levels of diesel-related hydrocarbons initially found in surface-water samples suggested to DWQ scientists that groundwater flowing into the bay had been contaminated by the spill.
However, a drainage system constructed to intercept contaminated groundwater seeping into Willard Bay appears to be working in decreasing contaminant levels both within and outside the shoreline collection booms, DWQ officials have said. The pipeline has been operating at 80 percent of normal pressure since early April.
The overall environmental impact of the spill is expected to be low. The DWQ's tests near the spill have shown trace amounts of hydrocarbons, not dangerous to humans or wildlife, in a minority of water samples.
Six beavers have been injured and are credited with building dams that blocked the flow of fuel into Willard Bay.
The DWQ has issued a Notice of Violation and Compliance Order to Chevron as a result of the spill. The state is asking Chevron to provide a report on cleanup activities and its response plan for the pipeline rupture.
Chevron will be required to submit a response to the compliance order by mid-June. Once Chevron's response to the notice has been received and reviewed, the state will begin a process to determine whether a penalty will be levied for the spill.
The Willard Bay leak is the third Chevron spill in the last three years in Utah. Two spills in 2010 near Red Butte Gardens in Salt Lake City leaked a combined 51,000 gallons of crude oil.