A 14-year-old boy was badly burned when a homemade firework he was holding exploded Sunday.

The boy and two friends apparently poured some gunpowder into a plastic pipe, Sandy Police Sgt. Kevin Thacker said. The trio was trying to shoot sparks out the pipe when it blew up about 6:30 p.m."He held up the pipe - trying to launch something out of it," Thacker said. "He received burns on the upper part of his body and lacerations from the shrapnel."

Paramedics transported him by medical helicopter to University Hospital, where he was in serious condition Sunday night. Police didn't release the boy's name.

The other two boys weren't hurt. The explosion happened outside a house at 2423 E. Alta Canyon Drive (8500 South).