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Crane Boom Incident Prompts NIOSH Report

According to the federal investigators, a 37-year-old Hispanic man who was killed while disassembling a lattice boom on a truck-mounted crane might be alive today if the employer had followed the crane manufacturer's safety recommendations and had provided training – in English and Spanish – on the correct procedures for disassembling cranes.

The man, who was a carpenter's helper, was killed on Jan. 30, 2006, while assisting the crane operator in removing pins that secured the lattice boom's 40-foot center section to the base boom section.

The incident – which occurred at a North Carolina bridge overpass construction site – and recommendations for employers are detailed in a National Institute for Occupational Safety and Health (NIOSH) Fatality Assessment and Control Evaluation (FACE) report.

"A Sense of Urgency"

The FACE report points out that the crew at the bridge construction site that day "was told that a truck carrying concrete bridge panel decking was on its way to the site and the decking needed to be off-loaded and placed on the bridge that afternoon."

"According to the crane operator, there was a sense of urgency to get the crane ready for the day's work," the report adds.

Although the site superintendent, crane operator and two carpenter's helpers assembled the 70-foot section of the boom, according to the FACE report, "the crane operator was left in charge of the crane assembly and disassembly." The crane operator asked the victim to help him remove the four pins – two upper and two lower pins – that secured the 40-foot center section to the 20-foot lower boom section.

When the second lower pin "would not budge," the victim picked up a pin that the crane operator previously had knocked out "and indicated with hand motions that [the crane operator] could use it as a punch to drive out the second bottom pin."

"The crane operator moved from under the boom and reached through the lattice and pounded on the pin held by the victim as the victim, located under the boom, held the first pin against the second bottom pin," the report says.

The crane operator reported to investigators that he told the victim to move out from under the boom – as the boom could fall – "and the victim moved from the center section to underneath the lower boom section."

"After the crane operator pounded on the pin about four more times with a sledgehammer, the second bottom pin came out," the report says. "The boom hinged on the top two pins and the lower boom section fell on the victim's back and pinned him to the ground."

According to the FACE report, the victim died of traumatic asphyxiation due to blunt force trauma.


To prevent similar incidents from occurring in the future, the FACE report offers three recommendations:

  1. Employers should ensure that manufacturer's safety recommendations for proper blocking and support procedures to prevent movement of boom sections are implemented when disassembling cranes. In this incident, the crane manufacturer's operating manual warns that workers should "never stand under a boom when removing pins" and that "incorrect disassembly of a pin-connected boom may result in machine damage, personal injury or even death."
  2. Employers should ensure that all workers assigned to disassemble or assist in disassembling cranes are trained on correct procedures, using a language and literacy level that workers can understand. The FACE report notes that victim in this incident "was not specifically trained in safety hazards associated with disassembling booms in English or Spanish and had never helped disassemble a crane boom before." It also points out that the crane operator "spoke English and, although a trained and certified crane operator, had never performed boom disassembly procedures as the lead worker before."
  3. Employers should ensure that pre-work safety meetings are conducted each day to discuss the work to be performed, to identify the potential safety hazards and to implement safe work procedures. Although the FACE report notes that, in this case, the company foreman or superintendent typically held a pre-work safety huddle – in English – each morning before work, on the day of the incident a safety meeting was not held.


To read the entire FACE report – "Hispanic Carpenter's Helper Dies After Crane Boom Fell on Him During Disassembly-North Carolina" – click here.

The NIOSH alert "Preventing Worker Injuries and Deaths from Mobile Crane Tip-Over, Collapse and Uncontrolled Hoisted Loads" provides recommendations for proper blocking and support of boom cranes during disassembly procedures. To read it, click here.

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