POWAY —— The assistant manager of Kragen's Auto Parts in Ramona was severely injured when a dry ice bomb he made exploded, authorities said Friday.

Lt. Edna Ito said 21-year-old William Stuckey was seen building the device in the store at 1935 Main St. and then carrying it out Thursday evening to the parking lot.

Stuckey screwed on the cap of the plastic bottle containing the explosive and started to shake the bomb with both hands about 6:30 p.m., Ito said.

Authorities said the bomb exploded, severely cutting Stuckey's hands between his thumbs and index fingers.

"It was a pretty powerful explosion," sheriff's bomb squad Sgt. Conrad Grayson said.

Ito said the wounds aren't considered life threatening. Stuckey was taken by ambulance to Palomar Medical Center in Escondido for surgery to both hands, she said. His condition wasn't available Friday.

Grayson said three felonies are being investigated —— making a bomb, possessing one and exploding one. The maximum sentence is a year in custody and a $10,000 fine.

The case will be sent to the district attorney's office, but usually if the bombmaker is the only person hurt no charges are filed, Grayson said.

"It will be up to the district attorney to make a decision," said the sergeant.