• U.S. Department of Labor
• Occupational Safety and Health Administration
• Directorate of Technical Support and Emergency Management
• Office of Science and Technology Assessment

Purpose

The purpose of this Safety and Health Information Bulletin (SHIB) is to:

• Warn employers and workers of the hazards involved in using stone-cutting machines; and
• Explain methods to eliminate or reduce the risk of injury when operating stone-cutting machines.

This SHIB describes prevention methods such as:

• Using machine-guarding methods that eliminate worker access to the cutting blades on stone-cutting machines, called the "point of operation;"
• Ensuring that machine-guarding components are properly installed and inspected daily, prior to use; and
• Providing information, instruction, training and supervision to workers on safe work practices when using stone-cutting machines.

Background

Stone-cutting machines, also called stone masons, stone cutters, stone splitters, and rock cutters, have hydraulically operated rams to split and cut various types of stone products used mainly for decorative purposes in the landscaping industry. The machines are produced in both stationary and mobile models. Their high-pressure hydraulic systems may be driven by combustion engine (gasoline/diesel) or electric motor.

Stone-cutting machines with unguarded cutting blades can cause amputations and other serious injuries. According to the Bureau of Labor Statistics, in 2010 (the most recent detailed data), 180 injuries occurred while using shears, which operate similar to stone cutters. Of these injuries, 100 were amputations and 50 were described as cuts, lacerations and punctures. Amputations can occur when shears or stone cutters are not guarded properly and a worker's hands or other body part is placed in the point of operation during operation.

Hazard Description

OSHA's Englewood, Colorado, Area Office investigated a landscaping products company that used a stone splitter to cut decorative rocks. Each rock was lifted by a forklift to a rolling conveyor table where the operator placed the rock under the cutting blades or the "point of operation" by hand. The operator then operated the hand controls with one hand and held the back of the stone with the other hand. This method of operation puts the operator's hand within inches of the unguarded point of operation and could result in severe injury, including amputation. In addition, the rock-splitting process often results in flying rock chips, which presents a hazard to the operator's eyes and face.

The Englewood office's investigation found that many of the stone cutters available for purchase pose amputation hazards because, typically, these machines are not designed with adequate machine guarding to prevent the operator from reaching into the point of operation.

OSHA worked with the stone splitter manufacturer and the landscaping company to retrofit the machine with two-handed controls, which prevented worker access to the point of operation. A cycle-initiation method was installed that requires constant, simultaneous pressure from each hand on two separate controls to move the cutting blades. If the operator removes either hand from either of the controls, the blades will stop immediately. This type of machine-guarding configuration is known as a "two-hand control."

The modification was easily engineered, relatively inexpensive, and readily accepted by the operators.

Retrofitted stone cutter with arrows showing top control button (added in the retrofit) and bottom controls (existing hand controls). The operator must press both the button and one of the hand controls to lower the blade.

Operator using the retrofitted stone cutter while wearing appropriate protective clothing (hearing protection, gloves, and faceshield).

Requirements and Recommendations

Under the Occupational Safety and Health Act of 1970 (OSH Act), employers are responsible for providing safe and healthful workplaces for their workers.

The following measures will prevent or greatly reduce the chance that a worker using a stone cutter or splitter will suffer an amputation or other serious injury:

• Identify the hazards of powered stone cutters and splitters prior to being used, asking questions such as:
• • Does the equipment have machine guarding at the point of operation?
  • Can the guarding be easily removed or bypassed?
  • Does the guarding keep the operator's hands, fingers, and body out of the danger area?
  • Is there evidence that the machine guarding has been tampered with or removed?
  • Could changes be made on the machine to eliminate the point of operation hazard entirely?
  • Are the machine manufacturer's recommended safety procedures available to the operator and being followed?

• Ensure stone cutters are equipped with machine guarding to prevent worker access to the point of operation, as required by 29 CFR 1910.212(a)(3)(ii) and 29 CFR 1926.300(b)(4)(ii). A good system eliminates the possibility of the operator or another worker placing parts of their bodies where they could be injured by hazardous moving parts. Examples of machine-guarding methods include two-handed starting devices, barrier guards, remote-operator controls, and electronic safety devices. This also includes the two-handed control retrofit described above.

• Conduct regular inspections and keep machinery clean and properly maintained. Good inspection, maintenance and repair procedures contribute significantly to the safety of the machine operator. Routinely inspect and maintain machinery according to the manufacturer's recommendations and good engineering practice.

• Identify other possible machine-related hazards that may pose a risk of injury and necessitate the use of personal protective equipment (PPE), as required by 29 CFR 1910.132(d) and 29 CFR 1926.95(a).

• Provide workers with PPE that adequately protects them from recognized hazards and ensure that it is used properly, as required by 29 CFR 1910.132(d)(1) and 29 CFR 1926.95(a). For example, provide safety glasses with side shields or face shields for workers exposed to eye hazards, face shields to protect workers' faces from flying rock chips, or gloves to protect workers' hands from cuts and abrasions from handling rock or stone.

• Train workers on the following topics:

• • All hazards in the work area, including machine-specific hazards;
  • Machine-operating procedures;
  • The purpose and proper use of machine-guarding, including instruction in the safe use and care of the machines;
  • Procedures for addressing unsafe conditions, such as, immediately reporting problems with machine guards; and
  • Safe use of PPE, as required by 29 CFR 1910.132(f).

• Provide adequate supervision and reinforce safe practices by ensuring that:

• • Only trained workers operate machinery;
  • Machine operators do not wear loose-fitting clothing, jewelry, or other items that could become entangled in the machinery; and
  • All other workers are prohibited from being near the machine during cutting operations.

Conclusion

Amputations from point-of-operation hazards, and eye and face injuries from flying rock chips, may result when workers use stone-cutters and splitters. Amputation hazards can be prevented by equipping stone cutters and splitters with two-hand controls or other devices that will prevent worker access to the point of operation, as well as providing adequate training in the safe operation of stone splitters. Eye and face injuries can be prevented by providing and enforcing the use of adequate eye and face protection.

References

The resources listed below provide more detailed information on machine guarding, controlling amputation hazards, and PPE use.

1. 29 CFR 1910.212: General requirements for all machines for general industry.
2. 29 CFR 1910.132: General requirements for personal protective equipment for general industry.
3. 29 CFR 1926.300: General requirements for hand and power tools for the construction industry.
4. 29 CFR 1926.95: Criteria for personal protective equipment for the construction industry.
5. Machine Guarding eTool: OSHA eTool.
6. Amputations: OSHA QuickCard Publication No. 3204.
7. Machine Guarding: OSHA Safety and Health Topics Page.
8. Amputations: OSHA Fact Sheet.
9. Occupational Noise Exposure: OSHA Safety and Health Topics Page.
10. Hazards Associated with the "Unintended (Double) Cycling" of Mechanical Power Presses: OSHA Safety and Health Information Bulletin SHIB No. 02-02-2010.
11. U.S. Department of Labor. Occupational Safety and Health Administration. OSHA Training Institute. Machinery and Machine Guarding Standards Course Objectives.
12. Safeguarding Equipment and Protecting Employees from Amputations (PDF): OSHA Publication 3170-02R (2007).