BOISE -- The Ada County coroner released the names Wednesday of two men killed Tuesday night after a trench they were working in collapsed.

The coroner’s office says 26-year-old Ernesto Saucedo-Zapata and 36-year-old Bert Smith Jr. died due to mechanical asphyxia due to compression.

The Boise Fire Department says Zapata and Smith were pronounced dead at the scene off of Gary Lane and Hill Road.

A third person, not identified, was taken to the hospital.

The Occupational Safety and Health Administration (OSHA) is the lead on the investigation and is working with both the Boise Police Department and Fire Department.

“This is the first trench-related death we've had in some time," OSHA Area Director David Kearns said.

The deaths of both Zapata and Smith spawned the investigation by OSHA.

“We do have an open investigation. Anytime there is a fatality, we are required to be notified and also to conduct an inspection," Kearns said.

Kearns says some things they'll look into for their investigation is what caused the accident and if there were any violations of safety or health rules.

“On this were there any precautions in place?" KTVB asked.

"Can't comment upon the nature of this investigation," Kearns replied.

The city of Boise says they did issue a permit to Hard Rock Construction for a sewer tap.

We contacted Hard Rock Construction and the person that answered the phone said the owners were busy at the time.

The Boise Fire Department says the trench was about nine feet deep when it collapsed. Kearns says anything deeper than five feet needs cave-in protections.

“Generally if a trench caves in then there was probably something that was missed as far as protecting workers.”

Kearns says many times when safety measures are missed it means those involved got in a hurry.

“They underestimate, they think it won’t' happen to them," Kearns said.

OSHA does do inspections on job sites, but Kearns says they only have seven inspectors for the entire state of Idaho, so they rely on employers.

“There needs to be a culture out there in the community where leaders, employers, workers, actually build that culture where it's completely unacceptable to be exposing workers to hazards,” he said.

Hazards, Kearns says, that are preventable.

“The commonalities with almost all these fatalities investigations that we look at is almost all of them are entirely preventable," Kearns said.

Many people who live near the construction site on Gary Lane have heavy hearts.

"I didn't know any of the men working, but just to think of them getting trapped and buried...it was just very sad," said Erica Cordova.

She picked flowers from her front yard and placed them near where the accident happened. Someone also brought a cross.

"It just makes us think of how precious life is," Cordova added.

OSHA officials say their investigation into the incident could take up to six months, but Kearns told us he hopes it will be completed before then.