State police say the two 17-year-olds were trying to make the bomb Friday afternoon when it exploded in East Fallowfield Township, Crawford County, about 45 miles south of Erie.

Police did not identify the boys, who they said put shotgun powder into a carbon dioxide gas cartridge like those used in gas-powered pellet guns.

One boy seriously injured his hand and was taken to Children's Hospital in Pittsburgh. The other boy received less serious shrapnel injuries to his chest and was taken to Meadville Medical Center, police said.

Neither boy's condition was immediately available early Saturday.

Police said the boys made the bomb for kicks.

"I'm sure it was just to make a big boom," said police Cpl. Lee Michael Formichella.