The student had a reaction to the rodenticide known as Thallium, Glen Rock Police Chief Dean Ackermann said.
All nine people taken to The Valley Hospital and Hackensack University Medical Center on Oct. 2 -- including the student -- were medically cleared, the chief said.
"As of this time none are exhibiting any signs of an adverse reaction," Ackermann said late Monday afternoon.
Glen Rock detectives working with the Bergen County Prosecutor’s Office determined that "the student had no intention of harming anyone at the school, nor any criminal intent," the chief said.
"The student, who was undergoing treatment at the hospital, was no longer in medical distress and was being further evaluated."
Police and EMTs from the Glen Rock Volunteer Ambulance Corps responded to the nurse's office around 8:30 a.m. Monday.
Members of the Bergen County and Glen Rock offices of emergency management and a Bergen County Hazardous Materials Team also responded to the school.
Hazmat techs identified the substance as Thallium, which is readily available online, Ackermann said. They contained it in a single room, tested it then removed it all from the building, he said.
Students were released from the school at noon and a decontamination service responded to clean the affected area, the chief said
All emergency services were cleared from the school by 2 p.m., he said.
Boyd A. Loving took the photos and contributed to this report.
Click here to follow Daily Voice Pascack Valley and receive free news updates.