The environmental review of one of the neighborhoods planned for the Newhall Ranch development was upheld in a Los Angeles Superior Court decision, the developer of the project announced Tuesday.

The decision set aside a 2012 complaint filed by the Santa Clarita Organization for Planning and the Environment, Friends of the Santa Clara River and three other organizations against the Mission Village neighborhood.

Newhall Land & Farming Co. plans to build more than 4,000 homes and an elementary school in the tract of 1,200 acres just west of Six Flags Magic Mountain theme park, with 600 acres set aside for open space.

Emile Haddad, chief executive of developer Five Point Communities, which owns Newhall Land, said the decision confirms the environmental analysis done by Los Angeles County was diligent and complete.

“We look forward to bringing to life this Mission Village community as part of the Newhall Ranch master plan,” Haddad said in a prepared statement.

The lawsuit, filed after the L.A. County Board of Supervisors approved the environmental impact report, claimed the review failed to analyze a host of factors that would impact the Santa Clara River, plants and animals, and the extent of how much PCE, a chemical degreaser, is on the property.

Dean Wallraff, an attorney with Sunland law firm Advocates for the Environment, which represented the environmental groups, said there will be an appeal. He said low concentrations of PCE were found on a former oil field on the property that closed in 2002.

“They are talking about a school and houses on that land,” Wallraff said. “”They should have done a more thorough sampling.”

Newhall Land & Farming Co., the developer of Valencia, is seeking to build 20,000 residences and 5 million square feet of office space over more than 2,500 acres in the larger Newhall Ranch project, which could take 30 years to complete.

The massive project has been delayed for years from lawsuits, which are still ongoing.

In February, a challenge to the environmental review of the Landmark Village neighborhood of Newhall Ranch was tossed in Los Angeles Superior Court. That decision is being appealed, Wallraff said.

In March, the state Court of Appeals upheld the environmental report approved by the California Department of Fish and Wildlife for the entire Newhall Ranch project. But Wallraff said the plaintiffs are seeking a review of the decision before the state Supreme Court.

Also in March, a lawsuit was filed in U.S. District Court in Los Angeles challenging the permits issued for Newhall Ranch by U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency.

Despite the announcement on Tuesday, the federal litigation is holding up the issuance of critical permits for any building to start.