Two decades ago, the sprawling grounds of the shuttered Lawrence Aviation Industries in Port Jefferson Station were littered with thousands of barrels leaking industrial solvents that created a mile-long toxic plume between the Sheep Pasture Road property and Port Jefferson Harbor.

Wednesday, state officials announced they had completed a $48.1 million cleanup of the federal Superfund site — a milestone that paves the way for new uses of the property, including a possible LIRR rail yard.

"This is a massive leap forward for this site today," Department of Environmental Conservation Commissioner Amanda Lefton said during a news conference at the site. Behind her on a wide swath of concrete were piles of debris and dumpsters filled with waste cleared from the site.

"Needless to say, this was a tremendous undertaking," she said.

Cleaning the property — a former aircraft parts manufacturing plant dating to Long Island's mid-20th century aeronautics heyday — once seemed a virtually insurmountable task.

Besides environmental contamination, Lawrence Aviation and its late owner, Gerald Cohen, left millions of dollars in unpaid property taxes and other debts. Cohen had been ordered to pay the cleanup costs before he died in 2020 but never paid a dime, officials said.

Various federal, state and local investigations had found numerous instances in which Cohen and Lawrence Aviation allegedly flouted environmental laws.

In the 1980s, company employees used a front-end loader to crush 55-gallon drums filled with hazardous material — even after Suffolk County health officials offered to help the firm comply with pollution control laws.

Cohen served a year and one day in federal prison after pleading guilty in 2008 to charges Lawrence Aviation illegally stored corrosive waste in two tanks at the site.

Cleanup efforts date back to 1987, officials said Wednesday. The site was added to the state Superfund list in 1993 and the national Superfund program in 2000, three years before the business closed. 

The state and federal Superfunds were established in 1979 and 1980, respectively, to fund hazardous waste cleanup. The programs launched in the wake of the Love Canal scandal, in which hundreds of families in that western New York community were evacuated to escape toxic waste contamination.

Lefton said the Lawrence Aviation cleanup included removing 17,000 tons of contaminated soil and 2,500 drums, containers and cylinders filled with polychlorinated biphenyls, or PCBs, asbestos and other hazardous material.

Demolition crews finished tearing down industrial buildings at the site last year, officials said.

With cleanup completed, DEC officials plan to remove all but five acres of the 126-acre property from the state's hazardous waste site registry. The public can comment until Aug. 3 on the proposed delisting on the DEC website, dec.ny.gov. 

The Suffolk County Landbank, a nonprofit arm of county government, took possession of the property in 2023 as part of a federal settlement of Cohen's legal cases. 

Since then, the land bank has sold about one-third of the property to Brookhaven Town for open space preservation. Another 40 acres are planned for a county-sponsored solar farm.

The Metropolitan Transportation Authority has tentatively agreed to buy the remaining 40 acres for $10 for development of a Long Island Rail Road depot, which would include electrification of the Port Jefferson branch, officials have said.

A June 30 deadline to complete the purchase has been extended up to one year, MTA and Suffolk officials said Wednesday.

Adrienne Esposito, executive director of Citizens Campaign for the Environment in Farmingdale, said the cleanup should serve as a model for returning contaminated sites to productive uses.

"This is a success story," she said. "This was a highly toxic site."