OSHA is investigating the death last week of an Illinois construction worker who died after being struck by a 70-pound falling beam at a worksite.

Michael Kerr, 57, was working on the construction site on Northwestern University’s Evanston campus on May 17 when a 16-foot-long beam on the sixth floor of a building was knocked off by a construction crane, according to a news release from police. The beam hit Kerr in the head and chest. He sustained multiple injuries and died at the hospital.

Kerr’s death has been ruled an accident, according to the Cook County medical examiner's office.

OSHA’s investigation into the incident could last six months. The agency is inspecting the construction site, interviewing employees and witnesses and checking to see what safety practices were used by the project's contractor, Power Construction Company of Schaumburg, Ill.

Sources say Kerr was close to retirement.