A New Jersey father and son are facing assault and other charges after an explosive mishap at a party over the holiday weekend spewed shrapnel through their neighborhood, authorities say.

Police arrested Thomas Kaiser, 60, and his 28-year-old son Erich at a party in Manville Saturday night after getting a call about an explosion in the Valley section of the borough — and at least one serious injury.

First responders treated a 34-year-old man for lower torso injuries at the scene and airlifted him to a trauma hospital.

Investigators say the Kaisers had allegedly tried to set off a signal cannon, a device designed to create a large boom and smoke cloud when ignited. Instead, it exploded, spewing shrapnel, authorities say.

An attendee of another party suffered serious injuries to his abdomen in the explosion. Several homes and vehicles were also said to be damaged.

Thomas and Erich Kaiser were released pending a first appearance hearing in Somerset County Superior Court. Attorneys for the men weren’t immediately clear.

It’s not Thomas Kaiser’s first step into fire. He was arrested in 2019 after bringing a cooler of fireworks to a Jersey Shore bar, forcing a scheduled Labor Day parade to be canceled. Thomas Kaiser was sentenced the following year to a year of probation.