June 16, 1986

The Seattle Regional Office has brought to our attention a potentially serious safety hazard related to the use of hydraulic tractor/semi-trailer dumper platforms. To illustrate the type of equipment used, we are attaching a copy of a photograph of a typical truck dumper system.

During a recent inspection conducted in Region X excessive wear in the hydraulic ram universal joint and numerous cracks in the platform beams were verified. Additionally, seven nonfatal collapses of this type of platform have een documented. The problem has the potential of causing fatalities. Generally, one to three workers are involved in activities related to this operation unless the establishment adheres to a strict policy which prohibits employee exposure.

The results of the field inspection conducted in Region X and the hazard evaluation of the system are outlined in the following points:

1. Jogging or shaking the platform when it is in the up position is sometimes used to facilitate unloading. This practice induces stresses on the dumper resulting in metal fatigue, cracks, and possible equipment failure. Shaking the trailer to move the material being unloaded may produce dangerous resonant frequencies that could further damage the components.
2. The load limit of the platform should be observed. Some of the older models of dumper platforms may not be designed to handle the new longer and wider semi-trailers which may be loaded beyond the capacity of the dump platform.
3. When employees are exposed, flow restrictors should be installed in the hydraulic cylinders at the hose entries. This is necessary to prevent rapid fall of the platform in the event of hose break.
4. Control stations should be installed at a sufficient distance from the platform to prevent the operator's exposure to the trailer should it break away and fall from the platform while the platform is in the up position.
5. It is important to maintain good housekeeping around and under the dumper. Excessive accumulation of debris can obstruct the freedom of operation and maintenance of the dumper deck and other components.
6. Excessive accumulation of debris on the deck can raise the trailer enough to cause it to jump off the dumper backstop. Inspection procedures, maintenance schedules, and safe work practices recommended by the manufacturers should be followed to minimize accidents. Periodic inspection by a registered engineer or manufacturer representative is advisable.
7. A lockout procedure should be established to protect workers during maintenance.
8. Means, including audible and visual signals, should be used to assure that employees are clear of the equipment during the dumping cycle.
9. In the event that employees must work underneath the dumper when it is in the up position, special procedures shall be taken to prevent the platform from falling onto the employees.

We recommend that compliance and consultation personnel be aware of the hazards addressed in this memorandum. Please disseminate this information to Area Offices, State Plan States, and Consultation Projects.