BOONTON TOWNSHIP - Investigators are working to determine what caused a deadly accident that killed two landscape workers in an excavated trench outside a Morris County home.

Boonton Township Police Chief Paul Fortunato says the accident occurred just before 4 p.m. Wednesday, when three crew members were excavating a drainage pipe at the Rockaway Valley Road home when the trench began to give away.

One worker became trapped and another man jumped in to try and save him, authorities said. But both men soon became trapped under about 10 feet of dirt. One other worker was able to escape with minor injuries.

Several technical rescue crews from around the state were called in to help reach the men.

One body was recovered in the late afternoon Wednesday, and the second man’s body was recovered overnight, according to township officials.

Police have not yet released the identities of the victims. Fortunato says representatives from the Occupational Safety and Health Administration (OSHA) are expected investigate the incident.