A superior court judge has temporarily stopped state regulators from approving the demolition and disposal of debris from a former nuclear research lab in Ventura County out of concerns the material is radioactive.

Sacramento County Superior Court Judge Allen Sumner ruled the Department of Toxic Substances Control must undertake an environmental review of plans to tear down the so-called Area Four site in Santa Susana currently owned by Boeing. A half century ago, the facility was home to nuclear research and rocket development and the site of a partial nuclear meltdown.

In August, environmental groups sued to stop Boeing from demolishing the facility and shipping the debris to area landfills. They later filed for a preliminary injunction to stop DTSC from approving the demolitions plans. Judge Sumner agreed to the injunction last week pending a trial on the original lawsuit.

In separate statements, DTSC and Boeing said they are reviewing the order to determine next steps.