| MSHA's Accident Prevention Program
| From 2001-2005, failing to block against hazardous motion was one of the most frequently cited regulations when investigating serious accidents and fatalities. Proper blocking against motion requires a risk assessment to evaluate the various pivot points and studying the job to ask, "what can happen?". Proper blocking includes using manufacturer provided safety pins, frame locks, and/or wooden blocking to prevent unwanted or sudden movement. For more information please see Blocking Raised Equipment AP tag # 93525 |
Accident: The victim was working in the articulation area of the front-end loader when it unexpectedly pivoted, crushing the victim.
Important: Never work or travel in the loader's articulation area without engaging the steering frame lock or without using another means of preventing motion.
Accident: The victim was removing toggle seat wedge bolts on a jaw crusher so that the broken pitman toggle seat could be replaced. The safety pins, provided by the manufacturer, had not been installed nor had other steps been taken to block/secure this component. The pitman assembly shifted and pinned the victim against the crusher framework.
Important: Before working on equipment, lock out the power and block equipment components from movement.
Accident: The front and rear sections of the front end loader had been separated at the articulation joint and each section was independently supported with jack stands. As the victim began climbing the ladder, he leaned against the separated rear portion. The rear frame of the loader tipped and swiveled to the left on the rear axle oscillation trunnion, pinning the victim between the left rear tire and the frame.
Important: Securely block equipment against all hazardous motion at all times while performing maintenance work. If the equipment being blocked has multiple degrees of movement of freedom, exercise extreme caution because some instability modes may not be obvious.
To prevent blocking of motion accidents: