Colorado Contractor Pleads Guilty to Manslaughter for Trench Death

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site of fatal trench collapse in breckenridge colorado
Members of the Red, White & Blue Fire Protection District respond to a fatal trench collapse November 16, 2021, at an A4S Construction site in Breckenridge, Colorado.
Red, White & Blue Fire Protection District

A Colorado contractor has pleaded guilty to manslaughter for the death of an employee who was killed in a trench collapse in 2021.

Peter Dillon, 54, pleaded guilty August 3, 2023, after being charged January 26 with reckless manslaughter. The former owner of A4S Construction of Vail was charged following the death of employee Marlon Alfredo Diaz, 23, who was installing a sewer line November 16, 2021, at a residential construction site overlooking the Breckenridge Ski Resort. Two other workers were also in the trench but were able to escape unharmed.

Inspectors with the U.S. Occupational Safety & Health Administration determined there was inadequate cave-in protection, among other violations. On December 20, 2021, OSHA inspectors also observed a similar violation of workers on the same construction site in a section of a trench that did not have cave-in protection.

“Between August and December 2021, the employer routinely assigned workers to work inside trenches that were not protected from cave-ins by an adequate protective system,” according to OSHA’s citation issued May 13, 2022.

A4S was issued penalties totaling $450,000. Dillon contested the violations, and the penalties were reduced to $100,000, according to OSHA online records.

“Our investigation found that this employer willfully sent workers into unprotected trenches at a site with a history of cave-ins and continued to expose workers to the same conditions even after the fatality,” said OSHA Area Director Amanda Kupper in Denver at the time of the citation.

OSHA issued the following violations against A4S on May 13, 2022:

(“Willful violations” are ones in which the employer either knowingly failed to comply or acted with plain indifference to employee safety. “Serious violations” are those when the workplace hazard could cause an accident that would most likely cause death or harm, unless the employer did not know or could not have known of the violation.)

  • Failed to use cave-in protection. Willful violation.
  • Failed to train workers on trench hazards. Willful violation.
  • Failed to provide a safe way for workers to exit the trench. A ladder should be available at least 25 feet from workers, but in this trench, it was 90 feet from workers. Serious violation.

“The reality is that this tragedy was 100% preventable,” said Heidi McCollum, district attorney for Colorado’s 5th Judicial District. “Employers who choose to take shortcuts to save money at the expense of the safety of their employees must be held accountable.”

Dillon is scheduled to be sentenced November 9. In Colorado, manslaughter is a felony punishable by fines of $2,000 to $500,000 and two to six years in prison.