LAS VEGAS (KLAS) — The “massive explosion” on Monday at a Boulder City business follows several fines issued in 2021 and 2019 by the Occupational Health and Safety Administration (OSHA).

In a 2019 incident, an employee lost a thumb in an industrial accident, records show.

OSHA reports show Armorock Polymer Concrete, a business that manufactures concrete products in a facility on U.S. 95 just south of Interstate 11, paid $12,912 in fines involving five workplace violations classified as “serious” found in a Dec. 28, 2021, inspection.

A tweet by Clark County on Tuesday afternoon said Building Department representatives will be inspecting the facility thoroughly “as soon as this afternoon.”

The 2021 violations involved:

  • Respiratory protection (2 violations)
  • Modifications/additions to powered industrial trucks
  • Grinding machine violations
  • Improper storage of oxygen cylinders

The 2019 workplace accident occurred when a steel plate fell on a worker’s hand as he was assembling and welding a steel mold for a cement product, OSHA records indicate. The worker was hospitalized and his thumb was amputated.

Armorock was fined $3,150 in that incident.

“When the employee was lowering the plate, the plate became separated from the magnet and fell. The employee had his left hand placed around the rim of the mold, with his thumb on top of the inside edge. When the steel plate fell, his thumb became pinched between the plate and the mold, severing the thumb,” according to OSHA records.

The explosion on Monday morning prompted a large emergency response, with about 45 emergency medical responders and a hazmat team.

Six employees were injured and two — including one person who had significant burns — were hospitalized, according to officials.

The investigation is continuing.