Rescuers attempt to free a worker who was buried up to his waist after the trench he was in collapsed Tuesday morning at a construction site in Forward Township. The man in his 40s was dug out by hand after being trapped about three hours. He was taken to an undisclosed hospital.

FORWARD TWP — Federal investigators are looking into the collapse of a trench at a construction site Tuesday morning that trapped a worker for three hours.

Rescuers said the man in his 40s appeared to be in stable condition as he was taken to a waiting medical helicopter.

The collapse left him buried to his waist in wet soil about 8:15 a.m.

The man was working at a construction site off Marburger Road in a trench that was 10 feet deep.

He was dug out by hand, pulled out of the trench on a stretcher and taken to an undisclosed hospital by STAT MedEvac helicopter shortly after 11 a.m.

The man worked for Mark Mashuda Excavating of Mars, said Steve Bicehouse, Butler County Emergency Services director.

According to Occupational Safety and Health Administration records, the company was fined in 2013 for several violations at two worksites in Allegheny County.

The records show that the company settled for $7,480 in fines for two violations and one repeat violation at a Gibsonia site and $2,600 for two violations at an Allison Park site.

Mark Mashuda Excavating did not return calls for comment.

Bicehouse, who also is the chief of the Evans City Volunteer Fire Department, said it took several hours to rescue the man because special trench rescue teams had to secure the trench to prevent a secondary collapse.

“Initially we couldn’t dig him out until we got the shoring in to prevent a secondary collapse. You have to take your time and be very meticulous,” he said.

During the rescue the man remained “awake and oriented” while paramedics monitored his vital signs, he said.

More than 50 emergency responders from a number of departments helped.

Two trench rescue crews, the Southern Butler County Technical Rescue Team and one from Chippewa Township, Beaver County, used special equipment to shore up the sides of the trench.

Construction workers also assisted by operating a backhoe and front end loader to help move equipment and to shore up the trench.

The cause of the collapse is unknown. However, Bicehouse said that a metal box designed to stabilize trenches was in place, but the man was trapped beneath it. He was trapped at the intersection of two trenches.

The property is the location for Peachmont Farms, a 94-unit housing development that was approved last year, according to Forward Township supervisors meeting minutes.

The properties are owned by America First Enterprises and Peachmont Farms LLC.

Officials from the Pittsburgh office of OSHA said the investigation could take up to six months, which is the agency’s statute of limitations, said Nick Maddamma, assistant OSHA area director.

OSHA does not have the authority to halt work at the construction site so the contractor could resume working once the emergency responders left, he said.

Agencies that responded to the accident included fire departments from Adams Area, Callery, Evans City, Middlesex Township, Penn Township, Aliquippa, Chippewa Township and Baden.

The Southern Butler County Technical Rescue, Quality EMS, STAT MedEvac, state police and Adams Township police also were there.