OMAHA, Neb. (AP) — Federal safety officials have begun investigating the explosion and fire that ravaged a restaurant and some apartments in Omaha’s Old Market district.

The Occupational Safety and Health Administration began its investigation late Monday. The agency’s Omaha director said if safe procedures had been followed, the explosion would not have occurred.

Authorities think a company working on a fiber optic project may have struck a natural gas line that leaked gas into the area. Several people have reported smelling gas before Saturday afternoon’s blast, which resulted in injuries to two people.