(AP) — A 63-year-old David City man has pleaded not guilty to charges in connection with a pipe bomb explosion during a July 4 celebration that seriously injured a teenage family member.

Russell Hilger pleaded not guilty Wednesday to second-degree assault, misdemeanor assault and five counts of criminal mischief. The charges carry a maximum combined sentence of 22 years in prison.

Hilger is accused of stuffing a 2-foot steel pipe with gunpowder and towels and lighting it at a family gathering at Ernst Lake. The pipe blast sprayed shrapnel that tore into the abdomen of 14-year-old Lauren Campbell of David City.

She lost her spleen and part of her pancreas, but has otherwise recovered.

A trial date for Hilger has not been set.