Petroleum products under the 100-acre Old Dutch/Aurora refinery site in Muskegon County's Muskegon Township have contaminated downstream groundwater and a county drain that empties into the Mona Lake watershed.
Details of the overall cleanup plan haven't been determined, and the Michigan Department of Environmental Quality must approve Findlay, Ohio-based Marathon's plans. Marathon spokesman Shane Pochard said the company expects to submit a plan to the state agency no later than early spring.
Under the agreement, the plan "may include cleanup, removal, disposal, on-site treatment, off-site treatment, active remediation, passive remediation, and/or remediation alternatives." That phase of cleanup is expected to start as soon as the summer.