(KTLA) — Several students were hospitalized after apparently overdosing on an unidentified narcotic at Johnnie Cochran Middle School in Los Angeles’ Arlington Heights neighborhood on Monday.

Los Angeles Fire crews responded to the school around 11:30 a.m. PT after receiving reports of at least three children “with altered level of consciousness after possible exposure or ingestion of a yet unknown substance,” the department said.

Nexstar’s KTLA confirmed the students responded well after being administered Narcan, which reverses the effects of opioids.

Three were transported to an area hospital where “they arrived conscious and breathing in minor to moderate medical distress,” officials said.

L.A. Unified School Superintendent Alberto Carvalho used the incident to encourage students and parents to report safety issues.

“We remain hopeful for a full recovery of our students … who suffered from a medical incident earlier today,” Carvalho said. “I urge everyone in our school community to download the LASAR app to anonymously report instances of suspicious activity, mental health incidents, drug consumption, drug trafficking, vandalism and other safety concerns.”

Los Angeles Police and L.A. School Police also responded to the school.

In December, 10 students at L.A.’s Van Nuys Middle School were evaluated by emergency responders after a suspected cannabis overdose. The incident was not fentanyl-related, crews at the scene confirmed.