UPDATE: Faulty Machinery, Not Propane Tank, Causes Afternoon Blast at Weston High School

While early reports indicated a propane tank explosion led to an evacuation of Weston High School this afternoon, the Weston Fire Department said faulty machinery was the culprit and that no propane has leaked into the school.

At about 1:54 p.m. today, fire and police responded to an industrial accident at the Weston High School science lab renovation construction site, originally believed to be caused by propane.

But Weston Fire Chief David Soar said the accident was caused by a faulty piece of machinery that runs off propane, rather than the propane itself.

Following the explosion, a 50-year-old construction worker sustained second-degree burns to his hands and face and was taken to Brigham and Women's Hospital, and students were evacuated.

No students were injured in the explosion and no structural damage occurred, Soar said, adding that students were ushered back into the building about 30 minutes after the explosion.

"(School personnel) handled everything very well," he said.

Responders tested the building to ensure no propane had leaked during the accident, Soar said.