Lockout/Tagout: OSHA’s Minor Servicing Exception

OSHA’s Control of Hazardous Energy Standard (29 CFR 1910.147), commonly referred to as Lockout/Tagout, was promulgated on September 1, 1989, and became effective on January 2, 1990. It is estimated that this OSHA standard prevents an average of 120 fatalities and 50,000 injuries each year. Employees performing maintenance, service, or repair tasks on powered machinery may face serious physical harm or death if proper energy control procedures are not followed. Injuries resulting from failing to control hazardous energy on powered machinery can include amputations, crushing injuries, electrocution, burns, lacerations, and bone fractures, among various others. The significance of OSHA’s Lockout/Tagout Standard with respect to powered machinery safety during times of maintenance or repair cannot be overstated.

Are There Exceptions to Following Lockout/Tagout Procedures?

The answer is yes, but it is important to emphasize that these exceptions must be closely evaluated to ensure that they offer the same amount of protection as that provided by Lockout/Tagout.

As opposed to following strict Lockout/Tagout procedures, there are a some noted exceptions within the standard that can be followed to protect employees from machine hazards. These would include the following:

  • Effective machine guarding (complying with OSHA’s Subpart O) that prevents employees from contacting the hazard or danger zones of machines (or machine guard devices that control an employee’s access to a machine);
  • Cord and plug equipment where the employee completing the maintenance has exclusive control of the plug during the service tasks being performed;
  • Testing or positioning of machinery; or troubleshooting of machinery that requires a power supply to complete (and allows for “temporary” removal of lockout devices while the testing/positioning is completed from a safe distance away from the hazard zones); and
  • Complying with OSHA’s Minor Servicing Exception.

Before getting into the specifics of OSHA’s Minor Servicing Exception, it is important to mention a few key points to provide a basis for understanding the exception. First, the Minor Servicing Exception is an exception, not the primary rule. In other words, when looking at machine safety during maintenance or servicing tasks, immediately relying on the Minor Servicing Exception should not be your regular course of action, as it may only be used under very specific conditions. Second, if utilized it is important to monitor the process and audit the people to ensure it is being used properly. Third, limiting the use of the minor service exception as only a small component of your overall energy control program will help ensure effective management of employee safety. And finally, when the exception is utilized, you must implement alternative protection measures that provide equivalent protection.

What is OSHA’s Minor Servicing Exception and What are Its Requirements?

OSHA’s Minor Servicing Exception is covered under 29 CFR 1910.147(a)(2)(ii)(B), which states that “minor tool changes and adjustments, and other minor servicing activities that take place during normal production operations, are not covered by the standard if they are:

  • Routine,
  • Repetitive, and
  • Integral to the use of the equipment for production, provided that the work is performed using alternative measures which provide effective protection.”

First and foremost, OSHA states that the minor servicing activity in question must be conducted during normal production operations, meaning while the machine or equipment is actually performing its intended production function. Or in other words, the mode in which an energized machine or piece of equipment operates to either manufacture a product or perform a function necessary to assist in the manufacturing process. Furthermore, the minor servicing activities must be inherent to normal production operations – meaning they are necessary to allow production to proceed without interruption.

Minor servicing tasks that occur during normal production operations may include clearing jams, lubricating machine parts, adjusting dials, inspecting certain sections within the machine, or clearing scrap. Minor servicing tasks typically do not require significant disassembly of a machine, heavy maintenance, replacement of multiple parts, set-up procedures, or annual service-related tasks.

Next, the activity must be:

  • Routine: The activity must be a regular course of procedure and be in accordance with established practices.
  • Repetitive: The activity must be regularly repeated as part of the production process.
  • Integral: The activity must be essential to the production process.

Finally, if all of these apply, the employer must use alternative measures to provide effective protection from hazardous energy. Some acceptable alternative measures include specially designed tools for machine access (vs. using hands/arms), remote devices, interlocked barrier guards or presence-sensing devices, machine start-up alarms and delays, exclusive control practices, machines with built-in control reliability and redundancy, training, and an implemented disciplinary system for non-adherence to trained-on practices.

A combination of these types of measures should be used to create a multi-layered protective process that would continue to protect the employee even in the event one layer of the process fails. These alternative protective measures must enable the employee to safely perform the servicing task without being exposed to the unexpected energization or activation of the equipment or the release of stored energy.

What Would be an Example of an Acceptable Use of the Minor Servicing Exception?

The clearing of jams is one of the more common examples where the minor service exception can often be applied. For example, in a plastic blow molding operation, it is fairly common that the plastic bottles may jam at the trimmer unit during the normal production operation. If the jams happen such that they are routine, repetitive, and integral to the process then the minor service exception may apply as noted in OSHA Compliance Directive CPL-02-00-147. A common minor service exception solution would be a multi-layered protective process such as: shutting off the machine, usage of control reliable interlocked guard access points, requiring the machine to be re-started at the control panel, and a 3-second start up delay and warning signal.

What Would NOT be an Example of an Acceptable Use of the Minor Servicing Exception?

The set-up and die change activities associated with the operation of mechanical power processes and power press brakes common to the metal working industry is a good example of something not covered by the minor service exception. Although upon first review this may seem like a task that could apply, it is not considered to be applicable by OSHA since the changes occur outside of the normal production operation. With this said, the use of lockout/tagout would be required as an element of the set-up and die change operations. OSHA explains this in chapter 3 of the CPL-02-00-147 Compliance Directive.


When utilized properly, OSHA’s Minor Servicing Exception can be a safe and efficient means to perform certain simple tasks during the operation of production machinery. But as outlined within this article, it is important to understand that multiple requirements must be met before it is acceptable to use. If those requirements cannot be met in full, the Lockout/Tagout standard is applicable, and the machine or equipment must be de-energized, and all potentially hazardous energy rendered safe.

If you need guidance or clarification on OSHA’s Minor Servicing Exception, contact your U.S. Compliance representative for assistance in ensuring a safe workplace for your employees.

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