Charles County police and medical officials were sent to an elementary school in Waldorf, Md., on Monday afternoon after eight students were seen passing around a bag of what was labeled as “edible candy” — food that sometimes contains cannabis.

School officials said a teacher at C. Paul Barnhart Elementary School noticed a group of children who seemed to be eating out of a bag of candy during recess. But after seeing the “edible” marking, the teacher confiscated the bag and alerted the school’s administration, according to an email to parents from Brian King, the school’s principal.

School administrators called 911 for medical assistance.

Police and school officials were uncertain Monday evening whether the confiscated bag of candy actually contained cannabis, according to the principal’s email. It was also unclear how many of the eight students ate from the bag, he said.

Charles County Public Schools deferred to Charles County Fire and EMS for additional information, but the agency did not immediately respond to requests for comment.

None of the students were transported by ambulance for medical treatment. All eight were returned to their parents Monday afternoon.

“Please know school administrators will immediately contact police any time a report involving alleged drugs, weapons or any other threats to the safety of our students and staff are reported,” King wrote in an email to parents.

School officials and police were still investigating the incident Monday evening.