Construction debris is dumped, sorted, crushed and plowed over at Lorton Construction Debris Landfill. (Dayna Smith/The Washington Post)

A controversial proposal to extend the life of an industrial landfill in Lorton has sparked a rare rift on the stubbornly collegial Fairfax County Board of Supervisors, whose members usually measure their differences in small degrees before votes that are often unanimous.

The board finds itself divided over whether to back residents who agreed in 2006 to live with an increase in the size of the landfill in exchange for a promise to shut it down in 2018 and replace it with a public park. They are outraged by a request by the site’s owner to keep it open an additional 22 years.

“About once a year, we have a split vote on a land-use case,” said Supervisor John C. Cook (R-Braddock). Lorton, he added, “might be this year’s vote.”

Supervisor Gerald W. Hyland (D-Mount Vernon), who represents Lorton, has strongly opposed the proposal by Manassas-based EnviroSolutions, which owns the site. But some of his colleagues are considering approving the request, potentially breaking a long-standing Fairfax tradition of deferring to the local supervisor on land-use cases.

“We obviously don’t have a lot of landfills, and I understand nobody would want to live near one. But by the same token, those folks generate waste, too,” said Supervisor Michael Frey (R-Sully). He added that he hasn’t decided how he’ll vote.

“It’s kind of like people who move near an airport and then complain about the noise,” Frey said. “I’m really trying to look at this from a countywide, regional perspective.”

EnviroSolutions applied to extend operations after realizing that the mountain of trash at the site, now nearly 360 feet tall, would not reach the maximum allowable height of 412 feet by the agreed-upon closing date.

In other words, there is still money to be made from construction companies who need a place to dump their debris.

The waste company’s request sparked intense local opposition, leading to aggressive lobbying from both sides and a crowded community hearing last month that ended at 3 a.m.

“If this application goes through . . . we’re gonna lose twice,” resident Dale Rumberger told Hyland and Sharon Bulova, the board’s chair, at a recent meeting, referring to the 2006 decision to allow the landfill to grow.

Now officials are working to find a compromise that would keep both the residents and the waste company from filing suit.

EnviroSolutions’ proposal includes environmentally friendly technology that aligns with Fairfax’s efforts to create a “Green Energy Triangle” in Lorton, the community near the Occoquan River long dominated by waste sites, heavy industry and, until it closed in 2001, a prison used by the District. In the past decade, a surge of new residential subdivisions have started to transform the area, fostering strong community organizations that have rallied to the anti-landfill cause.

EnviroSolutions offered to build a solar-panel farm, install wind turbines and lay down geothermal piping that could provide energy to surrounding buildings, including the Workhouse Arts Center, a struggling artists’ colony that was created on the grounds of the old prison. The center was taken over by the county earlier this year, with Fairfax assuming $30 million in debt to avoid an embarrassing foreclosure.

EnviroSolutions also offered $18.2 million to the county for recreation and other services in place of the park it had agreed to build on the site once the landfill closed. The company says it is no longer willing to build the park because the Fairfax County Park Authority has declined to pay for insurance that would cover any injuries there. The county said that when signing the deal, it made clear that insurance costs should be borne by EnviroSolutions.

The company’s request for an extension was warmly received, at first, by high-ranking Fairfax officials, including Bulova (D-At Large).

The company — which itself emerged from bankruptcy in 2010 — argued that the landfill is needed more than ever because of major construction projects in Tysons Corner and other nearby areas.

Last month, county staff workers recommended approval, which further angered local residents and some supervisors.

“At what point is the proffer system broken if you can make promises and then don’t keep them?” asked Nick Firth, president of the South County Federation of homeowner groups. If the park isn’t built and EnviroSolutions is allowed to keep the landfill open, he said, it would set a bad precedent for other county deals with developers and property owners.

Conrad Mehan, the company’s lobbyist, said EnviroSolutions wants to find common ground. The company is offering to pay $13 million to the county if it fails to deliver on its green energy promises or if the proposals fail to get required approvals.

“All the parties are going to have to realize they’re going to have to accommodate the objectives of the other side,” Mehan said.

Bulova expressed the same desire. She said she now has some doubts about the request to extend the landfill’s operations, despite her initial enthusiasm, and is unsure whether she will ultimately support it.

Among her concerns are plans by EnviroSolutions to widen the landfill, which the company said it must do in order to build a foundation on top of it to support the proposed wind turbines.

“It’d be like putting a landfill on top of a landfill,” Bulova said.

Appearing with Hyland at a community meeting in Lorton, Bulova spoke favorably of EnviroSolutions and, in particular, Mehan — a reliable donor to several political campaigns in the county in recent years.

But she said she was caught off guard by some of the plan’s details.

“Some people are counting votes, and you don’t know how people are going to end up voting in the end,” Bulova said.