A county corner has determined the June 13 death of a construction worker at the Deep Rock Tunnel Connector (DRTC) site in Indianapolis was the result of a head injury.

Twenty-five-year-old William Simpson died of “massive crushing blunt force traumatic injury of the head,” Alfarena Ballew, chief deputy Marion County coroner indicated Monday. Although Ballew ruled the injury an accident, it remains unclear how the incident occurred.

Simpson was killed more than 250 feet below grade while working on an overnight shift for the project, an eight-mile tube utility Citizens Energy Group (CEG) is constructing eliminate raw sewage overflows. Simpson, one of eight to 10 workers excavating the tunnel when the incident occurred, was employed by a joint venture of Walnut, Calif.-based J.F. Shea Construction Co. Inc. and Omaha, Neb.-based Kiewit Corp., which hold a $179.3-million contract with CEG.

The Indiana Occupational Safety and Health Administration (IOSHA) indicated it could take two to three months to complete an investigation of the accident. Although IOSHA has cleared the tunnel for reopen, it has restricted work in portions of the tunnel where Simpson was killed.

“The investigation is not only of the work site but of everything that led up to the moment that the incident took place,” an IOSHA spokesperson told reporters. “From our perspective, the site needs to be maintained for the integrity of the investigation.”

Another IOSHA spokesperson indicated the Shea-Kiewit joint venture has no record of safety violations on the tunnel or on projects elsewhere in the state.