Authorities say the death of a 19-year-old Illinois Institute of Technology student was an accident.

Benjamin Collen of Lincolnwood had been missing since Nov. 14. His body was found over the weekend inside a fraternity house storage room on the school's Chicago campus.

The Cook County medical examiner's office performed an autopsy Sunday. It ruled the cause of death was asphyxia due to inhalation of carbon dioxide from a canister.

Collen was a sophomore biomedical engineering major.

IIT President John Anderson has expressed condolences to Collen's family. He says the whole IIT community is in mourning.

The school is making counselors available for students.