A review of 28 sites in the Lander area has turned up five petroleum-impacted sites that could cost $500,000 to clean up.

As of last June, there were 1,613 contaminated tank sites in Wyoming. Of those, 1,104 have been remediated or resolved, 417 are currently in corrective action and the remaining 92 sites have been scheduled for future corrective action projects,

Currently, 420 of the remaining sites are in corrective action and the remaining sites have been scheduled for future cleanup.

Hal Hatfield, the Wyoming Department of Environmental Quality project manager, said some sites are at risk of hazardous vapors getting into nearby buildings.

Drinking water from private wells can be contaminated, and so can irrigation systems.

“Grass doesn’t grow well when it’s got gasoline or diesel in it,” Hatfield said.

A private consulting group in a 410-page report laid out cleanup plans for areas it found to have contamination at levels that require some form of remediation.

The next step is for engineers to complete design and specifications for each site, followed by a bidding process with construction contractors. Hatfield said he expects to be putting in remediation equipment in late summer or early fall.

The work is being paid for out of the Wyoming Corrective Action Account and with federal funds.

Hatfield said a vacuum truck will be used to suck out fluids and soil vapor from some sites. Remediation could also include installation of monitoring wells.

Other remedial methods include blowing air into the groundwater and drawing it out.

“We are monitoring it by taking groundwater samples on a quarterly basis,” he said. “We will do it for a period of time, and if we see over a couple of years it’s not cleaning up on its own, we will add chemical injections to help it out.”

That technique uses ozone that is forced into the ground to attack petroleum, breaking it down into water and carbon dioxide.