A student at Woodson said it had started during a demonstration of how fire can change colors. The chemistry lab also suffered some damage. Principal Scott Poole notified parents about the fire. Woodson school has about 2,100 students in grades nine through 12. They were evacuated to the school’s football stadium. The teacher, who also sustained non-life-threatening injuries, stayed behind to tell authorities what happened. The school was being ventilated. The incident comes after a difficult period at this top-performing high school: six Woodson students died from apparent suicides between 2011 and 2014, spurring parents to push for more mental-health resources.