The former owner of a Colorado construction firm pleaded guilty to a manslaughter charge Aug. 3 related to the death of an employee in a November 2021 trench collapse. The contractor, Vail-based A4S LLC, had not used required trench protections before the collapse, according to the U.S. Dept. of Labor’s Occupational Safety and Health Administration. 

Peter Dillon, who was the owner of the now-closed A4S, is scheduled to be sentenced Nov. 9 for the fourth-degree felony, the Fifth Judicial District Attorney’s Office announced. 

Twenty-three-year-old Marlon Alfredo Diaz and other A4S employees were installing a sewer line on Nov. 16, 2021 in Breckenridge when the more-than-5-ft-deep trench they were inside collapsed. Diaz was killed. One other worker escaped, and bystanders rescued another worker, according to OSHA.

Peter Dillon

Prior to the collapse, Dillon and A4S failed to train workers to recognize and control the hazards of trenches, according to an OSHA citation. The company routinely assigned inexperienced and untrained employees to work in trenches between August and December 2021. Also, an exit ladder was located about 90 ft from where work was being performed, but safe means of egress were required at least every 25 ft. 

About a month after the collapse, OSHA found workers on the same project had again been directed into a trench that had not been properly inspected. They were working below an undercut portion of trench outside of protective systems and exposed to another potential collapse, officials wrote in a citation. 

OSHA proposed penalties of nearly $450,000 for one serious and three willful violations. Officials settled the case against the contractor earlierthis year for $100,000, records show. Labor Dept. officials said they also referred the case to state prosecutors and recommended criminal charges. 

Heidi McCollum, the Fifth Judicial District Attorney, said in a statement that “this tragedy was 100% preventable.”

“Employers who choose to take shortcuts to save money at the expense and safety of their employees must be held accountable,” McCollum said. 

No one answered calls to a phone number listed for A4S. Court records identifying an attorney who could speak on Dillon’s behalf were not immediately available.

Dillon has agreed to forfeit any future ownership or leadership positions that involve trenching, excavation or oversight of workplace safety, according to OSHA.