OSHA Machine Guarding Standard

The Occupational Safety and Health Administration (OSHA) issued a Machine Guarding Standard for Agriculture.
OSHA Machine Guarding Standard - Articles


OSHA requirements are enforced on farms that employ 11 or more workers but safety recommendation are appropriate for all operators. The purpose of the standard is to protect all agricultural workers from hazards associated with moving parts on farm field equipment, farmstead equipment, and cotton gins used in agricultural operations. This publication provides farm employers with a concise summary of the standard requirements that make machines safer for employees and for employees to understand operating procedures. The OSHA Machine Guarding Standard requires the following:

Power Take-Off Guarding

All farm field and farmstead equipment must be provided with guarding of the power take-off. Farm field equipment is defined as tractors or implements, including self-propelled implements, or any combination used in agricultural operations. Farmstead equipment is agricultural equipment normally used in a stationary manner (e.g., material handling equipment such as a silo blower).

Under this rule, all agricultural equipment must have all power take-off shafts, including rear, mid, or side-mounted shafts, guarded by a master shield or other protective guards. When the master guard is removed for any reason, the equipment must also include protection from the portion of the power take-off shaft which protrudes from the tractor. Signs must be placed on tractors and equipment specifying that the safety shields must be kept in place.

Nip-point Guarding

All power transmission components on new field and farmstead equipment must be provided with nip-point guarding. Nip-points are "pinch or mesh" points on gears, belts, pulleys, etc. This portion of the standard is directed to farm equipment manufacturers. One special provision is where removal of a guard or access door will expose an employee to any component which continues to rotate after power is disengaged. It is the employer's responsibility to provide a readily visible or audible warning of rotation (employee must be able to see or hear it). Farm operations should have a safety sign that tells employees to look and listen for evidence of rotation and not to remove the guard or access door until all components have come to a complete stop. It is the employer's responsibility to purchase equipment that is properly guarded under current standards.

Prevention of Accidental Application of Electrical Power

Farm operations must provide a way to prevent accidental application of electrical power to farmstead equipment. All equipment, including existing equipment on farms, must have methods to prevent one person from starting a piece of equipment while another person is performing maintenance or service on it. These incidents can be prevented in the following ways:

  • Providing an exclusive, positive-locking means on the main switch which can be operated only by the person(s) performing the maintenance or service; or
  • In the case of materials handling equipment located in a bulk storage structure, by physically locating on the equipment an electrical or mechanical means to disconnect the power.

All circuit protection devices, including those which are built into an electric motor, must be of the manual reset type except where the employer establishes that the use of manual reset is not feasible. In this situation, the employer must provide:

  • An electrical disconnect switch within 15 feet of each motor and
  • A sign posted near each motor which warns employees that the motor could automatically start unless the electrical disconnect switch is utilized.

Operation and Servicing of Equipment

Employees must be instructed in the safe operation and servicing of equipment which they operate. At the time of assignment and at least annually thereafter, the employer must instruct every employee in the safe operation and servicing of all equipment with which they will be involved or will be involved, including at least the following safe operating practices:

  • Guards must be in place when the machine is in operation.
  • Never allow riders on farm field equipment other than persons required for instruction or assistance in machine operation.
  • Stop the engine, disconnect the power source, and wait for all machine movement to stop before servicing, adjusting, cleaning, or unclogging the equipment. The only exception is for a machine that must be running to be properly serviced or maintained, in which case the employer shall instruct employees as to all steps and procedures necessary to safely service or maintain the equipment.
  • Make sure everyone is clear of machinery before starting the engine, engaging power, or operating the machine.
  • Always lock out electrical power before performing maintenance or service on farmstead equipment.
  • Note: Tagging the locked out power source with a tag showing equipment is out of service is part of the lock-out/tag-out standard.

Although OSHA does not require that employers document that employees have been instructed about safe operation procedures, farm employers are advised to keep a record of this training activity. Employees should sign the dated record. This type of record may be useful when dealing with employee grievances, lawsuits, or insurance claims.

Prepared by Dennis J. Murphy, Professor of Agricultural Engineering