A small amount of depleted uranium caused a scare and led to a hazardous material response at a synagogue in Union County.

The marble-sized substance was discovered at Temple Sha'arey Shalom in Springfield on Tuesday. The Union County prosecutor says it was tested and was emitting a low-level pulse of radiation that was below the threshold that would be considered an imminent health hazard.

The material, which officials say was inadvertently left in a meeting room by an educator who used it as a teaching aid, was safely disposed of by the state Environmental Protection Department.

The U.S. Nuclear Regulatory Commission says depleted uranium is a byproduct of the process through which naturally occurring uranium is enriched to produce fuel.