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Derry high school teacher hurt when chemistry experiment explodes

| Wednesday, Oct. 24, 2012, 11:50 a.m.
A bottle of potassium nitrate lays on the ground outside of Derry Area High School after firefighters removed it from the school on Wednesday, October 24, 2012. Brian F. Henry | Tribune-Review
Derry Area High School students watch as chemistry teacher Brian Clawson is airlifted to a hospital after a lab explosion on Wednesday, October 24, 2012. Brian F. Henry | Tribune-Review
Medical personnel prepare to fly Derry Area High School chemistry teacher Brian Clawson to a hospital after he was injured in a lab explosion on Wednesday, October 24, 2012. Brian F. Henry | Tribune-Review

His face and hands burned and shirt collar ablaze, a popular Derry Area High School teacher hurried students away from an explosion in a chemistry lab Wednesday before he thought of himself, a student who witnessed the incident said.

Brian Clawson, 35, of Mt. Pleasant Township, a teacher in the district for about five years, was in fair condition in UPMC Mercy Hospital in Pittsburgh, according to a spokeswoman.

Paul Barnhart, a junior, was standing “4 or 5 feet” from Clawson as he mixed potassium nitrate and table sugar. Clawson was not wearing protective face gear as he stirred the mixture with a rod in a skillet-like container when it exploded about 11:40 a.m., Barnhart said.

“It was really, really startling,” Barnhart said. “His shirt collar was on fire, and he was covered in black stuff. After a minute or two, it ignited in his face.

“I was impressed he was more worried about getting the kids out (than about himself),” Barnhart said.

Another teacher ran to help Clawson, who was trying to pat out the flames on his clothing.

“‘I'm not doing good,” Barnhart heard Clawson say.

Clawson suffered burns to his face, neck, chest and hands, said Superintendent David Welling.

The explosion blew a powdery substance onto Barnhart's clothes and skin, and he suffered a minor burn to a leg. He sought medical attention as a precaution but said he and the other three or four students near Clawson were all right.

“I was probably the closest,” Barnhart said.

A girl sought medical treatment because she tripped during the school evacuation, said Assistant Superintendent Cheryl Walters.

Students waited on bleachers after the school was evacuated and watched the medical helicopter land. They returned to classes about 1:45 p.m.

Senior Laurie Campbell was in a classroom near the chemistry lab.

“It sounded like a desk drawer slammed against the wall,” she said.

Just before the explosion, Clawson had asked a student to open a window because of smoke from the experiment, Barnhart said.

As he lay on a stretcher waiting to be flown to the hospital, Clawson wondered whether air from the window caused the explosion, said Derry police Chief Randy Glick.

Walters said school officials were uncertain which chemicals were used in the experiment.

Clawson told students he had performed the experiment “three or four” times that morning. Junior Courtney Fillmore was in one of those classes.

“It sparked, but it did not blow up in my class,” she said.

Sugar, potassium nitrate and aluminum foil can be used to make a smoke bomb in a skillet or pan, according to the web page About Chemistry,

Dr. James F. Haw, professor of chemistry and director of the environmental studies program at the University of Southern California, said exposing the substances to air would have had no impact.

“You're mixing potassium nitrate, a main ingredient in gunpowder, so the possibility of an explosion should be anticipated,” he said.

Haw said the instructor and students should have been outfitted in protective clothing and face gear.

The federal Occupational Safety and Health Administration will investigate the incident because it involved a workplace.

Clawson “probably is the most popular teacher in the school,” Barnhart said.

“He's a really good guy,” said senior Felicia Pawlik. “The students really care about him.”

On Clawson's Facebook page, students and others posted best wishes Wednesday afternoon.

“You are in everyone's thoughts and prayers,” one wrote. “I hope you have a speedy recovery so you can go back to your family and be yourself again. ... Everyone loves you so much.”

“Mr. Clawson, you have every student, past and present, praying for you right now. I know you'll pull through,” wrote another student.

Earlier this month, a teacher at Albert Gallatin High School in Fayette County was injured in a chemistry lab accident. Bethany Herman suffered burns to her hands in the Oct. 10 chemical spill, school officials said.

Bob Stiles is a staff writer for Trib Total Media. He can be reached at 724-836-6622 or Joe Napsha contributed to the story.

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