HAMPDEN, Maine — A $900,000 settlement between the state and oil giant Chevron Corp. was revealed Friday in hopes of turning the page on an environmental mess that dates back more than a half century.

Gov. Paul LePage visited Hampden to announce Maine’s largest environmental settlement in 20 years, which attempts to remedy a site where an estimated 140,000 gallons of oil leaked into the Penobscot River from the 1950s to the 1980s.

“This is a tough but fair settlement that sends a message that we want to work with the private sector, but if they violate our laws we’re going to come after them,” the governor said Friday before a large crowd gathered outside Hamlin’s Marina.

The town of Hampden will receive $520,000 for a supplemental environmental project that will be known as the Turtle Head Cove Municipal Park. Plans call for an 8.5-acre riverside public park and boat launch that also will forever preserve environmentally sensitive land.

The remaining $380,000 will go into the Maine Coastal and Inland Surface Oil Clean-up Fund to help ensure that future spills are caught and remedied long before significant damage can be done.

Chevron’s penalty is the second-largest settlement in Maine history. International Paper paid approximately $1 million in 1991 for a series of air and water violations, according to the Maine Department of Environmental Protection.

By law, the settlement is subject to a 30-day public comment period, according to Maine Attorney General William Schneider, who echoed the governor’s sentiment that the deal sends a decisive message.

“We’re serious about pursuing civil penalties and taking actions so that the cleanup is assured and that those impacted receive the opportunity for enhanced enjoyment of natural resources,” he said.

In addition to the efforts that are part of the settlement, Chevron Corp. and the DEP have been engaged in remediation efforts at the site.

The DEP began uncovering the extent of the environmental violations in 2007 after issuing Chevron a notice of violation that it would investigate potential threats to public and environmental health posed by contamination.

That investigation led to a remediation plan submitted by Chevron that has resulted in the removal of 2,800 tons of oil-contaminated sediment and the recovery of nearly 10,000 gallons of oil at the site.

Patricia Aho, acting commissioner for the DEP, said Chevron has spent millions of dollars in the cleanup effort so far and likely will spend more in the future.

“This penalty, as significant in size as it may be, does not give Chevron a zero balance on the past,” Aho said. “But it allows us all to move forward beyond the enforcement action and focus on what is truly most important and that is: restoring the river, its banks, the ecosystems and the economy supported by its waters.”

No one from Chevron attended Friday’s event, but a company spokesman said this week that the oil firm agreed to the settlement to avoid a protracted legal fight.

“The state, while overseeing Chevron’s activities since 1984, provided Chevron no notice [or] indication of alleged violations until 2007 and did not demand any penalties until 2010,” Spokesman Sean Comey said in an email. “As part of the settlement, Chevron did not admit any liability, wrongdoing, responsibility, or illegal conduct whatsoever.”

Comey did say that Chevron was pleased that the fine will fund an environmental conservation project. The tank farm where the leaks occurred, which was sold by Chevron to Gulf Oil Corp., is no longer active.

Chevron said it operated its tank farm and marine terminal in Hampden between the 1950s and 1986, when Cumberland Farms Inc. purchased the Gulf Oil brand assets for the Northeast, which included the terminal and tank farm. Cumberland Farms has not been linked to the contamination. The tank farm and oil terminal closed in 1996, according to a Cumberland Farms spokeswoman.

Susan Lessard, Hampden’s town manager, credited Chevron for agreeing to work with the state and the town on an amicable solution.

“They could have simply negotiated how big a check to write to the state of Maine for this penalty but they didn’t,” Lessard said. “They expended an enormous amount of time, effort, energy and money to collaborate with the town on the development of this [park] project.”

The Hampden Town Council must vote next Monday on whether to accept the town’s role in the settlement agreement. Lessard said the waterfront park is a great opportunity for Hampden.

The public park in Hampden also is expected to spur the business expansion of both Hamlin’s Marina and McLaughlin’s Seafood, which recently opened a restaurant at the site.

Although the extent of the environmental damage caused by oil spilling into the river may never be known, those who gathered Friday were focused on efforts to turn the incident into something positive.

“This project will be a permanent positive example of what can happen when business and government work together for solutions to difficult problems,” Lessard said.

The Associated Press contributed to this report.