A legal challenge that prompted city education officials to rewrite all of its co-location plans was denied today.

Well before the co-location was approved in February, parents at Brooklyn’s PS 9 had battled against the city’s plan to move Brooklyn East Collegiate Charter School into the building. In April, then-State Education Commissioner David Steiner halted the co-location plan, agreeing with the parents that the city Department of Education’s space-sharing plan had many flaws. After the city revised the planalong with all of the other co-location plans that had the same problems — parents appealed again.

Today, state officials rejected that appeal, clearing the way for Brooklyn East Collegiate to take over classrooms and some shared space in the Prospect Heights building this fall.

The decision comes as a blow not just to PS 9 parents but to others across the city who are trying to prevent co-location plans from moving forward. Steiner’s April ruling on PS 9, which has come to be known as the Espinet decision, emboldened groups of people at other schools facing co-locations this fall to file their own appeals with the state. In recent weeks, State Commissioner of Education John King dismissed two other appeals, allowing site plans for Coney Island Preparatory Charter School and Explore Charter School to move forward.

Today’s decision did not come from King, but from his deputy, Valerie Grey. King recused himself from the case because he used to be the managing director of Uncommon Schools, the network of charter schools that includes Brooklyn East Collegiate.

The space-sharing plan could still be disrupted if the lawsuit filed by the UFT and NAACP to stop school closures and charter school sitings is successful. The PS 9 co-location is not among those the lawsuit seeks to halt, but if the DOE is blocked from closing a third school in the building, MS 571, there might not be space to add Brooklyn East Collegiate. A decision in that lawsuit could come this week.