Colorado contractor awaits sentencing on manslaughter charge after failing to protect employees in 2021 trench collapse that killed 23-year-old worker

BRECKENRIDGE, CO – The owner of an Avon construction company whose failure to follow required federal safety standards led to the 2021 trench collapse death of a 23-year-old employee in Breckenridge now awaits a November sentencing date after pleading guilty to manslaughter on Aug. 3, 2023.

The plea follows a criminal referral by the U.S. Department of Labor after Peter Dillon and his now defunct company, A4S LLC refused to require the use of proper safety equipment to protect his workers. The refusal contributed to a trench collapse in which a company employee, Marlon Diaz, suffered fatal injuries as he installed a residential sewer line.

After an investigation of the incident by the department’s Occupational Safety and Health Administration, A4S LLC received three willful citations in May 2022 for not ensuring the excavation was inspected by a competent person, failing to instruct employees on the recognition and avoidance of unsafe conditions and not having a trench protective system in place. OSHA also issued the company a serious citation for not having a safe means of exit within 25 lateral feet of employees working in a trench.

In addition to its citations, OSHA proposed $449,583 in penalties and placed the A4S LLC in its Severe Violator Enforcement Program. A4S LLC has since shuttered and Dillon agreed to forfeit any future ownership, leadership or management position that involves trenching or excavation, or the oversight of workplace safety and health.  

“Federal regulations require employers to provide a workplace free of recognized hazards and yet, Peter Dillon willfully sent Marlon Diaz and other employees at a location with a history of cave-ins to work in unprotected trenches,” said OSHA Regional Administrator Jennifer Rous in Denver. “Even after the fatal collapse, Dillon continued to endanger employees at the site.”

Collapses and cave-ins pose the greatest threat to trenching and excavation workers. In 2022, OSHA reported that at least 39 industry workers died. From 2011 to 2018, the Bureau of Labor Statistics reports 166 workers died in trench collapses.

“Marlon Diaz’s life could have been spared if Peter Dillon had required the use of safety equipment that was lying unused near the trench when it collapsed,” explained Regional Solicitor John Rainwater in Denver. “We deeply appreciate the work of the Summit County District Attorney’s office in holding Peter Dillon accountable and will continue to work closely with OSHA and local, state and federal prosecutors to bring employers who fail to protect employees as the law demands to justice.”

OSHA has a National Emphasis Program on trenching and excavations. Trenching standards require protective systems on trenches deeper than 5 feet. Additionally, trenches must be inspected by a knowledgeable person and have a safe means of entering and exiting prior to allowing a worker to enter.

Learn more about OSHA.