HONOLULU (HawaiiNewsNow) - An excavator operator working at a Kauai recycling plant was treated for severe burns last year after accidentally triggering a massive blast that was caught on camera — and authorities believe they know who will be held accountable for the explosion.

Surveillance video of the blast, which was obtained this week by Hawaii News Now, appears to show the arm of the excavator moving near the ground just moments before a giant fireball appears on screen.

Seconds later, a man believed to have been the excavator’s operator comes running into the security camera’s field of view with his shirt in tatters.

The explosion burned scrap metal in the Puhi yard and shattered the excavator's windshield. Labor attorney David Simon says it's one of the worst workplace accidents he's ever seen.

"My gut reaction is the devastating force, what it could do to a human body," said Simon. "Nobody should have to be exposed to that kind of danger."

Kauai officials say the victim was a 39-year-old Hanapepe man who suffered second- and third-degree burns to his arms and torso. He was treated at Wilcox Memorial hospital, and sources say he has since returned to work.

After the blast, the state Labor Department fined the recycling company more than $11,000 for safety violations. The fines were later rescinded after an investigation found that the blast had been caused by explosive material that was brought to the recycling yard by an unidentified landscaping company.

The landscaping company, according to the labor department, did not disclose that the box contained explosive material. Sources say the landscaper obtained the explosives from a construction firm that uses them for rockfall mitigation work.

"Someone who buys a tool like that has a duty of care to at least warn (people), so it doesn't just get thrown in a dump where a poor innocent guy gets very badly injured," Simon said.

The state Labor Department has finished its investigation and closed the case, but a civil lawsuit against the construction company is expected to be filed.