Photo from NSW Trade & Investment Mine Safety Investigation Report of a 2014 fatality of worker, crushed while using a mobile elevated work platform. Photo shows the approximate position (after recovery of worker). Incident Report

Summary
Entrapment and crushing injuries in boom lifts most often occur when the operator is reversing, slewing, or elevating the platform into an unacknowledged obstruction. Unexpected movement of the boom is also a contributing risk factor. According to International Powered Access Federation data from 2012, 19 entrapment fatalities occurred in 2012.

When an operator of an aerial work platform becomes trapped between the control panel and the obstruction, serious injury or death can occur. Often the operator puts himself or herself into this risky situation by leaning over the guardrails or control panel to observe the wheels or base while traveling in an extended boom lift. Other hazards include uneven ground conditions, poor visibility at height, distractions (people or objects) in the path of the aerial work platform, placing objects in the platform that fall against the controls, and driving at high speed.
 
When an operator becomes trapped against the controls while the aerial work platform is traveling, the operator may no longer be able to control the movements of the machine, increasing the likelihood for serious injury or death.

Best Practices

• Review Best Practice Guidance for AWPs on this topic published by the International Powered Access Federation and other useful resources. 
• When elevating near obstructions use controls in this sequence: drive, elevate, slew, telescope, fine control.
• Maintain suitable ground conditions. Do not operate on soft ground, adjacent to steps or over voids, or service ducts.
• Do not lean over platform controls while moving.
• Don’t put objects in the platform that could activate or obstruct the controls.
• Always check the direction of movement of the aerial work platform with reference to the direction arrows on the AWP base and platform controls before activating the control.
• Select AWP models that feature trip devices integrated into the controls that cut power if the operator is pushed over the controls.
• Consider adding secondary guarding solutions to your fleet of aerial work platforms. Check with the manufacturer of your equipment for aftermarket enhanced control protection. One example is the Skyguard® accessory from JLG, which features reverse functionality when about 50 pounds of force are applied. It temporarily reverse most functions that were in use at the time of activation. 
• Read IPAF’s Guidance on Secondary Guarding Devices.