This is an archived article that was published on sltrib.com in 2013, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

Chevron still can't account for thousands of gallons of diesel fuel three weeks after a pipeline spill at the Great Salt Lake.

The latest update from the "Unified Command" said nearly 3,000 gallons remain in the soil, wetlands and water at Willard Bay, just south of the Bear River Migratory Bird Refuge.

Tuesday's report also reduced a previous estimate of how much diesel leaked. Around 21,000 gallons spilled out of a six-foot split in the pipe nearly three weeks ago — roughly 6,000 gallons less than earlier projections — according to the incident-oversight group, which includes Chevron, the Utah Division of Water Quality and the U.S. Environmental Protection Agency.

"Cleanup and remediation activity continues to make steady improvements in restoring the area impacted by the diesel spill at Willard Bay, with a goal of reopening the Willard Bay North Marina and Park in early June," said the Unified Command in its fourth news release since the March 18 spill.

Chevron restarted the pipeline on March 30 after approval from the U.S. Department of Transportation's Pipeline and Hazardous Materials Safety Administration.

Meanwhile, 167 workers continue removing diesel from the 7 acres affected, a spot west of Interstate 15 at the Willard Bay State Park North Marina that extends into the popular fishing and boating site, the adjacent wetlands and a large irrigation reservoir. Chevron is also excavating contaminated soil and replacing petroleum-coated vegetation and brush.

So far, the spill's biggest impact has been on six beavers that lived in the wetland lodges that initially helped block the diesel's flow into the bay. They are still recovering at a wildlife rehabilitation facility in Ogden.

Walt Baker, the state's top water-quality regulator, said Chevron has installed a drain to capture groundwater that appears to be leaching traces of petroleum into the bay below the water's surface. His agency is working with the Utah Department of Health on fish consumption guidelines for the popular catches at the state park despite the low level of contamination.

Baker's office expects to hand the pipeline company a violation notice by the week's end, he said. After two crude oil pipeline spills at Red Butte in 2010, the state fined Chevron $500,000 and ordered cleanup, long-term monitoring and $3 million in waterway projects.

"There are pollutants that have been discharged illicitly, without a permit," he said of the latest spill.

Tage Flint, general manager of the Weber Basin Water Conservancy District, is already pushing for long-term monitoring.

Although his district does not use the reservoir for drinking water, and no imminent danger to people or the environment is seen, Willard Reservoir is the district's largest water resource and might be needed someday for drinking water.

"It seems to us they are on the right track" with the cleanup," he said. "But it's that subsurface stuff that we're worried about."

Twitter: @judyfutah