Westlake Boys High School in Auckland has been evacuated after a chemical explosion in one of its laboratories.
Firefighters were called to the school shortly after 2pm after a jar of bromine exploded.
Fire Service shift manager Jaron Phillips said the chemicals had now been isolated inside a hazardous materials drum.
Fire crews were still at the scene, including a hazardous materials unit, which was decontaminating the area and airing the building.
Mr Phillips said there were no reports of injuries.
