More than a dozen youth soccer players were sent to the hospital for observation after they complained that chlorine fumes made them feel ill.

The incident happened at a soccer camp held at Drew University in Madison. Officials say that 14 players between the ages of 10 and 17 complained of shortness of breath, difficulty speaking between breaths, nausea and “general airway issues.”

Officials say that “a small amount” of cholerine was accidentally released into the pool, which made the players feel ill.

“Tests detected normal levels of chlorine and all systems were working as normal,” a spokesperson for the town said.

The players were treated at the scene and also taken to Morris Town Medical Center for observation.