FORT LAUDERDALE, Fla. — Officials say 26 students and one adult staff member from a South Florida high school have been hospitalized, including some who had seizures, after possible exposure to an unknown substance.

Fort Lauderdale Fire Rescue officials say students began feeling ill Monday after being in the gym at Cardinal Gibbons High School, a private Roman Catholic school. Some students experienced seizures, others had nosebleeds or shortness of breath and some passed out.

The South Florida Sun Sentinel reports that paramedics and a hazardous materials crew responded to determine if the illnesses were the result of an exposure to some type of substance.

The Fort Lauderdale Police tweeted that the area of concern was isolated, and there was no need for parents to pick up their children.