The Los Angeles Unified School District board voted 5-2 to abandon a toxic site where the nation’s costliest high school was under construction.

Interim Superintendent Ramon Cortines had asked board members to delay their vote for 60 days to give the district more time to study alternatives to scrapping the school.

Board members made their decision Jan. 25 after presiding over a meeting that included hours of impassioned pleas from community members who lobbied for or against completing the high school downtown.

The Belmont Learning Complex was supposed to be the crown jewel of the nation’s second-largest school district, giving a home to some 5,300 students in a desperately overcrowded part of downtown. Instead, construction was halted over environmental concerns after the district spent $170 million.

The complex was built on an old oil field in a crowded, low-income neighborhood, and officials fear it could be contaminated with hydrogen sulfide and methane gas that could form explosive pockets under the foundation.

Prior to the board’s vote, Cortines proposed transforming the school into an administrative office and warehouse, because environmental standards for adults are not as strict as they are for children. Critics came from all sides.

The contentious battle was played out in a beleaguered district that recently lost its superintendent, in part, because of the Belmont debacle.

District personnel slated to move to Belmont said they feared for their safety. Neighborhood residents and students, upset by overcrowded conditions and long bus commutes to other schools, held rallies urging completion of the high school.

The teachers union opposed its completion based on safety concerns and criticized the district for the expense. It could take more than $200 million to resolve the issue, said Day Higuchi, president of the union that represents 42,000 teachers, counselors, psychologists, and other professional staff.

“Our main concern is that, like everyone else, we had serious questions even before they voted to go ahead with it as to its safety,” Higuchi said. “Also, this is an incredibly expensive school.”