Click to watch raw video from Tomball High School

TOMBALL -- Half of Tomball High School in northwest Harris County has been evacuated due to a chemical spill. A school district spokeswoman said a science teacher preparing an experiment for class, spilled some amyl alcohol, which prompted the evacuation.

The Tomball Fire Department Haz-Mat team was on scene at the school.

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Tomball Haz-Mat crews prepare to go into Tomball High School after a chemical spill Friday morning.

Several hundred students attending classes in rooms near the science lab were taken out of class and were for a while held in the nearby football stadium. School district officials said 10 teachers and five students were treated and released from Tomball Regional Medical Center while two other students remained in the hospital.

Students that were being held in the football stadium were taken to other classrooms at mid-morning. By 11 a.m., the all-clear had been sounded and classes resumed.