OLONGAPO CITY: More than 50 students of the Olongapo City National High School (OCNHS) were taken to a hospital here Tuesday afternoon after inhaling ammonia that leaked from an ice plant at the back of the school. Six of the students, were still under observation at the emergency room of the James L. Gordon Memorial Hospital (JLGMH) while the rest have been sent to their homes after receiving medical treatment. The leaked chemical appeared to have come from a broken check valve of a refrigeration tube the plant uses in making ice. Some students also suffered minor injuries as they scampered from the area, according to rescuers that responded to the scene. JLGMH Hospital Administrator Jesse Jewel Manuel, said no less than 60 students were taken to the emergency room mostly complaining of difficulty of breathing and dizziness. Olongapo City Mayor Rolen Paulino has ordered the cancellation of classes in the school on Wednesday as the plant was being inspected.