OWN OF MAPLE GROVE, Wis. (AP) — Sheriff’s investigators in Wisconsin are willing to forgo any possible underage drinking violations in order to get more information about a bonfire explosion that injured more than a dozen people, including some critically, officials said Tuesday.

The Shawano County Sheriff’s Office says as many as 40 current and former Pulaski High School students were at the bonfire Friday night in the Town of Maple Grove, which is about 25 miles (40.2 kilometers) south of Green Bay.

The sheriff’s office believes the explosion was triggered when someone pushed a 55-gallon drum containing diesel fuel into the fire.

Investigators say 17 people injured were privately transported to hospitals after the explosion. Seven of those were transferred to Ascension Columbia St. Mary’s Hospital in Milwaukee to have their burns treated, WLUK-TV reported. Authorities say a number of the injured remain hospitalized, some in critical condition.

“We understand there may be some apprehension for some to meet with us based on the evidence of underage drinking, and although underage drinking is something law enforcement agencies take seriously, we can assure those who were there, that our detectives do not have intentions on issuing citations for this, as our main focus and concern is gathering the facts of this tragic event,” the sheriff’s office said.

A number of people have come forward with information, investigators said, but there are other witnesses to the explosion who have not.