FACEValue: Worker crushed by collapsing crane boom
NIOSH’s Fatality Assessment and Control Evaluation Reports
Date of incident: March 2008
An adult male sustained fatal injuries when the crane boom he was disassembling buckled and crushed him. The victim was not an employee of the construction company that owned and operated the crane – he was a friend of the owner. The victim was assisting the owner in disassembling the truck-mounted lattice boom. With the pendants attached to the tip, they lowered the boom until the tip was approximately 4.5 feet above the ground. According to the owner, the connecting pins were not supposed to be removed until the pendants were moved to another section of the boom and the tip was cantilevered. However, as the owner was disassembling the hook block near the tip end, the victim began to remove both the bolts and the connecting pins between extensions. As he drove out the last pin, the boom buckled and fell on him. The owner immediately called 911 and paramedics arrived within minutes. The victim was transported to a hospital where he was pronounced dead.
To prevent future occurrences:
- Ensure all personnel assigned to assemble or dissemble a crane boom have received training on safe procedures. A large number of fatal crane injuries occur during crane assembly and disassembly. Removing the wrong pins can cause the booms to collapse when not properly blocked. Employers should only allow thoroughly trained workers to assist in assembling or disassembling a crane boom. A written work plan should be prepared and reviewed.
- Consult the manufacturer for updated operating and maintenance procedures and safe work practices when working with older crane models. The crane involved in this incident was a 1967 model, purchased used. Manuals for older models may not include currently accepted safety procedures, so an updated manual should be obtained from the manufacturer. Use the following boom disassembling tips as an additional guide:
- Lower the boom until it is horizontal with the ground, and rest the boom tip on blocking until the pendants are slack.
- Move the pendants back no farther than the cantilever length allowed in the manual.
- Raise the boom up slightly and remove all lower pins on the sections ahead of the pendants.
- Use a longer bar to drive the pins out if the cotter pins are inside the boom. Do not climb under the boom to remove pins.
- Make sure every boom section is supported, then lower onto the blocking. Remove the upper pins on the sections ahead of the pendants, and then remove the sections.