PLYMOUTH – More than 50 individuals, towns and businesses originally determined to have supplied waste oil to a recycling company that then incorrectly dealt with the oil will be notified next week that they may not have to fully participate in costly cleanup reimbursement.

Almost 80 parties applied to the U.S. Environmental Protection Agency as part of an inability-to-pay settlement regarding cleanup at the Hows’ Corner Superfund Site. At the site, incorrect handling of the waste oil resulted in groundwater contamination.

According to officials involved in the cleanup process, the EPA mailed letters Thursday notifying 55 parties of their full or partial release from the payback obligation.

From the 1950s to 1980, more than 517 businesses, towns, school districts, military bases, industries and utility companies disposed of waste oil at the 17-acre Portland-Bangor Waste Oil Site in southern Plymouth. Contamination at the site led to a new, alternative water supply for 36 surrounding homes.

Cleanup at the site, which included removing 850 tons of contaminated soil and installing the alternative water source, cost more than $6.5 million, 60 percent of which will be paid by the EPA.

Altogether, more than $2.6 million of those cleanup costs have been billed to more than 130 entities that supplied oil to the site. The issue is further complicated, because in the past 50 years, more than half of those companies that used the site have closed or gone out of business.

The payback requirement has angered those getting the bills because the Maine Department of Environmental Protection advised them to use the Hows’ Corners site for oil recycling.

The amount of cleanup money owed is based on the amount of oil shipped to the site. For example, Prouty Ford in Dover-Foxcroft is being asked to pay more than $30,000 towards the cleanup. The city of Bangor’s share is more than $40,000. Bangor International Airport is being asked to pay $36,518.

Other companies and towns have been assessed at prices ranging from less than $10,000 to nearly $300,000.

David Littell is a Portland attorney and chairman of the PRPs, a group of 104 “potentially responsible parties” that attempted to have all or a portion of the cleanup amount waived, based on inability to pay. Littell said Friday that the EPA has mailed letters to each of the PRPs that requested a waiver.

“Of the 79 parties that applied, 55 have been offered some sort of settlement,” he confirmed. He said the settlement offers are being kept confidential by the EPA but that individual PRPs should begin receiving notification today or Monday.

“Obviously, there will be 24 very unhappy parties,” he said.

Those agencies, towns and businesses that will be forced to repay cleanup costs can participate in a loan program passed in April by the Maine Legislature.

LD 1408, a legislative bill that originally was a grant program, was amended to create a loan program for those affected entities. It shifted $3.1 million from Maine’s Rainy Day Fund. Loans will be available to those who owe up to $75,000 to the EPA.