More than a dozen people, including seven children, were hospitalized after becoming suddenly sick at a Jersey City day camp.

The incident occurred in the pool area at Lincoln High School at 60 Crescent Ave. The illnesses are believed to have been caused by a reaction to chlorine in the air, according to fire officials.

"One of our camp counselors went over you know, we sent them with them," says Rosa Roney, site supervisor. "He came running back ? he said somebody needs to get over there; the kids are all throwing up."

Other symptoms included breathing problems and skin irritation. Hazmat crews and firefighters were called to the scene and moved the children outside.

Fire Chief Michael O'Reilly says a worker mistakenly mixed chlorine for the pool filter incorrectly. The worker allegedly panicked after his mistake and dumped the mixture in a toilet, causing too much chlorine to get into the air.

Thirteen people in total were taken to Jersey City Medical Center and Bayonne Hospital. Authorities say all are expected to go home Tuesday night and are doing fine.