An explosion inside Chestnut Accelerated Middle School in Springfield, Massachusetts has sent an Assistant Principal to the hospital and forced an evacuation. Two devices were found, but only one went off. The injured administrator suffered a “minor injury” as a result of the blast. According to WWLP Television, police are currently questioning two 8th graders in connection with the case.

The Worcester Telegram reports that the ‘bomb’ may have been a soda bottle bomb, “made from a household chemical and a soda bottle.”

Here’s the thing about soda bottle bombs like the one described in the Telegram