Hazard Summary

Two workers on a construction project were struck and killed when a structural steel beam being hoisted over them slipped out of a lever-action beam clamp.

The investigation revealed that the single clamp being used was too large for the beam and so did not grip the top flange securely. It was also discovered that the clamp used a lever action for gripping. When the tension on the hoist cable was released, the jaws of the clamp could open automatically and release its grip on the flange.

Clamps of this type do not meet the requirements of the Regulations for Construction Projects [O. Reg. 213/91, section 172], which state that "a container, sling or similar device for rigging or hoisting an object, including its fittings and attachments . . . shall be so arranged as to prevent the object or any part of the object from slipping or falling."

Beam clamps that rely on the lever action of the jaws to provide the grip on the beam do not meet the requirements of the Regulations for Construction Projects and therefore should not be used for hoisting structural steel.

Required Action

  • When a beam clamp is used for hoisting, it must be positively attached to the beam, i.e. attached by a bolting mechanism or similar device that will prevent the beam from slipping or falling.
  • An identification plate that clearly indicates the load rating and the method of attachment to the beam must be affixed to the beam clamp.
  • When long or irregularly shaped beams are being hoisted, a two-point beam attachment and a spreader beam should be used.
  • The load must never be hoisted over workers.

For additional information, please call the Ministry of Labour Health & Safety Contact Centre.

This resource does not replace the Occupational Health and Safety Act (OHSA) and its regulations and should not be used as or considered legal advice. Health and safety inspectors apply and enforce these laws based on the facts they find in the workplace.