CHICAGO (CBS)– For the sixth time in two weeks, someone released pepper spray inside Morgan Park High School.

A 17-year-old male is in custody and police said charges are pending.

Police responded to the incident on the second floor of the school just before 10:30 a.m. Tuesday.

According to the Chicago Fire Department, 11 students were transported to local hospitals.

There have been five other incidents involving possible pepper spray releases at Morgan Park since April 25.

On Thursday, someone released an aerosol substance inside the school. Sixteen students reported injuries. Three were taken to the hospital.

A day earlier, three people were hospitalized when a substance was sprayed or released into the air.

Two students were taken to the hospital last Tuesday afternoon, after someone sprayed an unknown substance.

The week before, police and fire crews were called to Morgan Park High School two days in a row — on April 25 and 26 — after students were sprayed with an aerosol irritant, possibly pepper spray or mace.

“CPS is taking this situation very seriously and we will double down on our efforts until we are confident the situation is fully resolved,” Chicago Public Schools representatives stated in a written statement. “Morgan Park High School is an IB school that provides enriching academic opportunities for its students and our highest priority is ensuring students have a safe learning environment. We will continue ongoing safety and engagement efforts until these incidents come to a stop.”

CPS said they have implemented additional school security measures.

Students tell CBS 2 they do not want to see their classmates ending up in the hospital.

One Morgan Park High School junior said school officials are checking backpacks every morning.

“That’s not normal at all. We usually just go through the metal detectors and go to our class, but the last week class started getting put 30 minutes behind, because they had to check everybody’s bags,” he said.

Chicago Teachers Union President Jesse Sharkey argues heightened security measures will not do the trick. He said the recently announced cuts to Morgan Park’s teaching staff will only make things worse.

“You really need to have enough staff and personnel in the building with relationships with students,” he said.

Special meetings have been held with staff and small student groups to try to solve the problem.