MAPLE GROVE, Wis. (AP) — An 18-year-old who triggered a bonfire explosion that injured more than a dozen people at a backyard gathering in eastern Wisconsin has been sentenced to a year in jail and five years probation.

Sam Armstrong appeared Thursday in Shawano County Court, WLUK-TV reported.

Armstrong pleaded no contest in February to 13 counts of injury by negligent use of an explosive. A no-contest plea is not an admission of guilt but is used as such at sentencing.

Armstrong was attending a bonfire on Oct. 14, 2022, with other teenagers in Maple Grove, about 25 miles (40 kilometers) northwest of Green Bay, when he threw a barrel containing a mix of gasoline and diesel into the fire, sparking an explosion that burned at least 17 of the roughly 60 youths who were there, authorities have said.

He told police he didn’t know his actions would cause an explosion and injure anyone, according to a criminal complaint. Armstrong told investigators he had been drinking beer.

He faces several civil lawsuits filed by some of the people who were injured in the explosion.

Benjamin Van Asten, one of those injured in the explosion, told the court Thursday that he forgives Armstrong’s “one little slip-up” and that Armstrong was “trying to be cool in front of all of his friends.”

Speaking from remarks prepared by Armstrong, defense attorney Greg Petit told the court that his client was sorry, ashamed and embarrassed.