As many as 30 students taking part in a marching band competition at Penn High School fell ill to heat-related illnesses on Saturday, Sept. 23.

With a daytime high expected to hit 90 degrees and a heat index in the mid-90’s, St. Joseph County Dispatch says the calls started to come in just before 3 p.m., according to 95.3 MNC’s reporting partners at ABC 57.

Students were preforming outside during the annual Carnival Of Bands for about two hours before a decision was made to move the event inside the school’s gymnasium, ABC 57 reported.

While many of the students were treated on scene, more than a dozen were taken to the hospital.

More than 30 bands were scheduled to compete at the school. However some bands, including Plymouth High School, decided not to compete because of the hot weather.

Read more details about the heat-related illnesses with ABC 57.