At 8:30 a.m. on August 1, 2020, Employees #1, #2, and #3, employed by a
electrical services company in the telecommunications field, were
working on a multi-employer construction project at the intersection of
two streets. They were potholing to locate underground utility lines,
with the aim to then bore in a new fiber optic line under the
intersection. After finding what they thought was over-pour from the
concrete curb, they used a Ring-o-matic Vacuum Excavator to excavate
over top of the concrete. They then used a jackhammer on the concrete.
The jackhammer bit made contact with a 12,470-volt underground
electrical distribution line, and an electric arc explosion occurred.
Employees #1 and #2 were killed by electrocution. Employee #3, who was
knocked down by the force of the explosion, was transported to the
hospital, where he was observed, determined to have no injuries, and
released.
Source:osha.gov