Officials say several children have been discharged from a local emergency room after experiencing nausea and vomiting

More than two dozen children fell ill, suffering nausea and vomiting, on Thursday at a Florida summer camp — and no one knows why.

Officials tell PEOPLE that 33 children mysteriously became sick at Camp Cloverleaf 4-H in Lake Placid, on the same day and were rushed to local hospitals. The campers range in age from 8 to 13 and officials say at least three adults were sick as well.

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“Happy to report that all youth and adults have been discharged from the ER,” camp spokeswoman, Heather Kent, tells PEOPLE. “The health department is on the scene and is investigating. We are waiting for the results of their investigation.”

Highlands County Public Safety Director Marc Bashoor told the Washington Post that one child who had been vomiting fainted, and staffers called 911. Then, Bashoor said, “like dominoes, kids started throwing up.”

In a statement to PEOPLE, camp officials said the remaining 87 campers who were not sick returned home on Friday, “as they normally would have on this final day of the camp.”

Image zoom Camp Coverleaf 4-H in Lake Placid, Florida

The camp will be “thoroughly disinfected,” according to the statement, as new campers are expected to arrive on Monday.

“[Four]-H Camp Cloverleaf is maintained and cleaned on a regular basis to ensure the health and safety of campers,” the statement said. “All camp staff are trained to respond to medical emergencies, and they are certified in first aid and CPR.”

Camp officials are working with the Highlands County Department of Health to determine what happened to the kids. In a Facebook post, Bashoor called the incident “interesting.”

“We have NO IDEA at this point on the cause – nothing ruled in, nothing ruled out… although CO is very unlikely,” Bashoor wrote on Thursday, likely referring to carbon monoxide poisoning.

He told the Post that the illness could be food-related, or there could be an amoeba in the water. However, health officials continued to investigate on Friday.