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Hazards of Transporting, Unloading, Storing and Handling Granite, Marble and Stone Slabs
Safety and Health Information Bulletin
Unloading stone slabs from containers, storing them in "slab-racking" systems, moving and handling stone slabs with equipment, and loading stone slabs onto trucks can be dangerous. This Safety and Health Information Bulletin (SHIB) discusses ways to minimize caught-by, crushed-by, and struck-by hazards associated with these work tasks. Awareness of the appropriate precautions highlighted in this SHIB can help prevent serious injuries and fatalities related to these activities.
The purpose of this SHIB is to:
Serious injuries and fatalities occur during the handling, loading, and unloading of large heavy stone slabs. Stone slabs can vary in weight from several hundred to several thousand pounds. OSHA addressed this concern in 2005 by issuing a SHIB detailing the hazards associated with transporting and unloading stone slabs from delivery trucks. That SHIB did not address, however, the hazards associated with the unloading of stone slabs from containers or other unique in-house handling hazards that could result in serious injuries and fatalities.
OSHA’s Integrated Management Information System (IMIS) data from 1984-2006 confirms that 46 fatalities nationwide were associated with the handling and storage of stone slabs. Unsafe handling and transportation of stone slabs have resulted in many other serious injuries as well. OSHA’s Region VIII Englewood, Colorado Area Office reported that 11 of the 46 fatalities associated with handling and storing stone slabs occurred in their region during stone yard activities. Additionally, Region I reported three fatalities within an eighteen-month period associated with the storage of stone slabs in "slab racking" systems. These fatalities took place in Massachusetts, Rhode Island and Connecticut. In each case, the employee was crushed between several slabs weighing from 4,000 to 6,000 pounds. OSHA’s Chicago North Area Office also investigated two fatal accidents and two serious injuries involving unloading slabs from containers.
A summary review of the accident investigations revealed that employees were killed or sustained crushing injuries from slabs shifting inside a container or when unloading slabs using industrial forklift trucks equipped with boom attachments.
Unloading, storing, handling, moving, and loading stone slabs present a variety of hazards that require specific safety procedures. The following is a summary of the hazards that have been documented.
Unloading Stone Slabs from Containers
Wood supports are provided by some suppliers to prevent bundles of slabs from shifting inside containers during shipping. Without the wooden supports, the slabs can shift, slide, and/or collapse. Employees have removed these supports when unloading and have become trapped or crushed from unanticipated shifts or collapsing slabs.
Stone slab container with wood supports in place
Employee was crushed after removing wood supports.
Storage of Stone Slabs
When the slabs are off-loaded, they are often placed in a rack structure for storage. These racks may be constructed of metal and/or wood. One type of racking system uses an A-frame structure. The slabs are placed against the back of the A-frame or against another slab.
In some cases, the A-frames were not designed properly to support the weight of the slabs or to prevent the remaining slabs from shifting when one slab is removed. In other instances, the slabs were not secured with restraining devices and/or tie-downs to keep them from sliding, nor were the A-frames inspected to ensure structural integrity.
In order to position stone slabs near vertical (90 degrees), employees sometimes stand in front or behind the slabs (within what is known as the "fall shadow"). Standing in the fall shadow can result in a crushing injury or fatality should the slab tilt too far.
The "slab rack" is another storage system that is used throughout the stone slab handling industry. Several companies manufacture and distribute these types of storage systems and all are of a similar design. These "slab racks" consist of two horizontal bases and poles. The bases have holes fabricated in the top and bottom for insertion of the poles. After the poles are installed in the base, the stone slabs are placed between the poles. Placement and removal of slabs are performed by material handling equipment.
"Slab rack" base with pole fully inserted.
Failure of this racking system is common. Overloading the rack from the weight of the slab can deform the base causing the pole to come out of the bottom hole. When this occurs, the pole is held in place only by the upper part of the base, creating instability, which can result in the failure of the slab rack.
Failure of the "slab racking" system.
The bottom of the pole was not inserted
into the base.
The presence of objects or other debris in the base holes can also prevent the full insertion of the pole into the base, causing instability.
Debris preventing the complete insertion
of the poles into a "slab rack."
Handling and Moving Stone Slabs
Mechanical equipment, such as cranes and powered industrial trucks, are often used to transport stone slabs within a facility. Hooks, chains, clamps, straps and other lifting devices are also used as rigging. Often an employee acts as a spotter to assist in the transfer of the stone slabs.
Illustrates employees staying out of the slab’s fall shadow
during slab transport.
Prior to moving stone slabs from the racks to the work area, employees may be exposed to a crushing hazard when attaching a clamping or lifting device. Typically, a wedge is used to create a space between the slabs prior to attaching the clamping/lifting device. In numerous instances, however, employees have either placed themselves between the slabs or they have improperly positioned the wedge between slabs. Both of these instances resulted in employees being crushed when slabs shifted and leaned.
Illustrates the use of a wedge from the end of the slab. If
slab failure should occur, the employee will not be in the
Loading Stone Slabs onto Flatbed Trucks
Stone slabs are loaded onto a flatbed truck with mechanical equipment such as a powered industrial truck with a boom or an overhead crane. The flatbed trucks may have A-Frame supports, or pole racking systems to secure the slabs for transport. Employees who are engaged in loading stone slabs are exposed to caught-by, struck-by, and/or crushed-by hazards.
Employers who are engaged in the handling and storage of slabs must prevent caught-by, struck-by, and/or crushed-by hazards in their workplace. The following are general recommendations:
The following recommendations will minimize the potential hazards associated with "stone racks" and other storage racks for storing stone slabs:
The following recommendations will minimize the potential hazards associated with handling and transporting stone slabs:
Edwin G. Foulke, Jr.
Occupational Safety and Health Administration