Shoes squish on soil and oil rises to the surface, and brick and lumber surface from a possible coking plant on the banks of the North Platte River near First Street.

Wednesday, dump trucks hauled logs from the south to the north side of the river where an excavator's bucket opened its jaws, bent down and bit on the logs, picked them up, dropped them, covered them with dirt and tamped them to form new banks.

The rehabilitation now includes remediating vast newly found pollution from when oil production and refining dominated the city and contaminated the river.

Those days are gone, but the consequences and the costs remain.

"We are estimating right now, and I want to emphasize right now, we are $526,000 of environmental work that is not in our budget to cover, nor should the city have to cover it," Jolene Martinez told the city council at a work session on Tuesday.

"We estimate that when we get into this we may be well into a million or more dollars of environmental work that we do not have budgeted," said Martinez, assistant to the city manager.

The $526,000 bill includes the construction work, monitoring and water testing for hydrocarbons, dissolved hydrocarbons and heavy metals, she added.

This remediation should have been performed by BP, the city and the Wyoming Department of Environmental Quality when the former Amoco/BP refinery site was cleaned up in the early 2000s, Martinez said.

Since then, the city has focused on rehabilitating portions of the river damaged by invasive species and eroding banks.

For the new phase, the city in August awarded the $2.6 river rehabilitation project Shamrock Environmental Corp., which began construction in late September and was expected to finish by June.

Contamination was expected, but not like this, Martinez wrote. "No one expected, however, to find a good deal of unmitigated pollution remaining in this stretch of the river."

The work so far only has been on the north side of the river, and the next phases include the south side of the river, and two sections downstream.

Booms have been placed in the river to stop oil sheens, and the remediation has discovered heavy metals, Martinez said.

Crews could have kept digging indefinitely oil-contaminated soil to east of the First Street Bridge, so the DEQ advised the project managers to encapsulate the contamination, place topsoil over it and plant vegetation, she told the council.

The heavy equipment also uncovered the remains of what probably was a coking plant that had been demolished but left the brick, lumber and pollution, Martinez said.

The area between the Jonah Bank and the river will be fragile until vegetation takes hold, so steps have been installed to a bench by the river, she said.

Tuesday, Martinez said the DEQ estimated the remediation will delay the completion to late next year.

The city has been in productive discussions with BP, which already has pledged $100,000 towards the cleanup, she said.

Council member Mike Huber asked whether the work on the river dislodged the contamination.

Martinez said the eroding banks had been releasing contaminants all along. "Did we unleash the pollution? No your honor, we did not."

Ken Bates asked if the released pollution would affect Evansville and ranches and farms down the river.

Martinez responded the booms are catching hydrocarbons, and river users downstream have been notified, especially Evansville because it takes its water from the river.

Mayor Charlie Powell said the city will front the money for the cleanup and wait for reimbursement.

"It's got to be done anyway," Powell said. "If it wasn't us, it would have been somebody else later to fix this problem."

Tom Morton, Townsquare Media