Two children briefly lost consciousness and then regained it Friday at Winslow Township Elementary School No. 1 in Camden County, and the cause is under investigation, authorities said.
The children are believed to be twins, authorities said. They were examined by emergency responders and treated at the scene.
The call came in just before 11:30 a.m. at the school on Inskip Road, authorities said.
County hazmat crews tested the air quality but found no issues, county spokesman Dan Keashen said.
Students and staff were placed in a room as the crews swept the building, police said. They then returned to class.