A back-tax agreement between the city of Glen Cove and an investor that wants to lease land near the city’s southern border to Costco will help jump-start development of the site, representatives of the city and investor say.

The city council is slated to vote on the agreement Wednesday night.

The site, about 15 acres on Sea Cliff Avenue off Pratt Boulevard, was until 2007 home to a manufacturer of circuit boards, Photocircuits Corp. The environmental contamination left behind and the company’s bankruptcy resulted in a legal morass that has helped prevent development, officials said.

One stumbling block has been a dispute over the assessed value of the land and how much in back taxes dating to 2011 that investors owed the city. Investor Spectrum Origination LLC had challenged the city’s assessed valuation of the land at more than $8 million.

The agreement reduces that assessment to $2.5 million and the amount of taxes to $1,055,000. Glen Cove owes Spectrum $300,000 from a previous reduction of taxes after Spectrum’s successful challenge of assessments, Mayor Reginald Spinello said. The new agreement is for Spectrum to pay the city $700,000.

Spinello said the settlement is fair, because Manhattan-based Spectrum could have plausibly argued that the millions of dollars of environmental remediation needed on the land effectively reduced its assessed value to zero. It removes a stumbling block to finally developing the site and increasing tax revenue to the city, he said.

advertisement | advertise on newsday

Laureen Harris, a Uniondale attorney for Spectrum, said there have been “serious discussions” between Spectrum and Costco for the Issaquah, Washington-based retail giant to build on the site. Costco would lease the land from Spectrum and another investor, with the consent of the Nassau County Industrial Development Agency, the owner of the land, she said.

A Costco spokeswoman said the company does not comment on potential future locations.

The IDA is the owner because of a tax break it granted years ago to Photocircuits, Harris said. Spectrum is an investor because Photocircuits owed it money when Photocircuits went bankrupt, she said.

The state Department of Environmental Conservation began remediation in 2012, Harris said. Tests of the land found groundwater contamination, DEC documents say.

The DEC so far has spent $3.4 million from the state Superfund on the cleanup, the agency said in an email. The DEC said it plans to speed up remediation if the site is developed.