Lockout Tagout (LOTO) Standards: What OSHA 1910.147 Requires

29 CFR 1910.147, "The Control of Hazardous Energy (Lockout/Tagout)," requires employers to develop written, machine-specific procedures that isolate hazardous energy before employees service or maintain equipment, and to train, inspect, and document that program on an ongoing basis, not just write it once. It's one of OSHA's most frequently cited general industry standards for a reason: most of the ways employers get cited are procedural gaps, not equipment failures. OSHA estimates that proper compliance with this standard prevents roughly 120 fatalities and 50,000 injuries each year. This guide walks through what the standard actually requires, piece by piece.

What Triggers a Lockout/Tagout Requirement?

1910.147 applies whenever employees service or maintain machines or equipment where unexpected energization, start-up, or release of stored energy could cause injury. Two narrow situations fall outside that requirement:

• Cord-and-plug-connected equipment where unplugging it achieves complete deenergization, and the plug stays under the exclusive control of the employee doing the servicing.
• Minor tool changes and adjustments during normal production operations, but only when the work is routine, repetitive, and integral to the production process itself, and the employer uses alternative measures that provide effective protection. This exception is genuinely narrow; it does not cover most maintenance work, and treating routine maintenance as "minor servicing" is one of the more common ways employers misapply this exception.

What Does a Written, Machine-Specific Energy Control Program Require?

Outside of the narrow exceptions above, OSHA requires written energy control procedures specific to the machine or equipment being serviced. A generic, facility-wide "lockout policy" alone doesn't satisfy this. Each procedure needs to address:

• Shutting the machine down and notifying affected employees before servicing begins.
• Identifying and isolating every energy source: electrical, mechanical, hydraulic, pneumatic, chemical, thermal, or gravitational.
• Applying the lockout or tagout device to each energy-isolating device.
• Relieving, restraining, or otherwise rendering safe any residual or stored energy.
• Verifying isolation, typically by attempting to start the machine through its normal controls, before work begins.

What's the Difference Between Lockout and Tagout, and Why Does OSHA Prefer Lockout?

These two terms get used almost interchangeably in casual conversation, but the standard treats them very differently. A lockout device physically restrains an energy-isolating device in the safe position. A tagout device is a warning only; it doesn't physically prevent anyone from re-energizing the equipment, it just tells them not to.

Because of that gap, OSHA requires employers to use lockout whenever the energy-isolating device is capable of accepting a lock. Tagout is only permitted when the isolating device can't be locked out, or when the employer can demonstrate that a tagout program provides employee protection equivalent to lockout, a standard that's genuinely difficult to meet. Programs that rely on tagout also carry extra obligations: additional training on the limitations of tags (a tag can never be bypassed, ignored, or removed by anyone other than the person who applied it), and more rigorous periodic inspection requirements, covered below.

Who Needs Lockout/Tagout Training, and What Does Each Group Need to Know?

The standard defines three categories of employees, and conflating them is a frequent, citable mistake:

• Authorized employees are the ones who actually perform lockout or tagout to do the servicing. They need the most extensive training: recognizing hazardous energy, understanding the type and magnitude of the energy sources present, and knowing the specific methods and means to isolate and control them.
• Affected employees operate or work near the equipment being serviced but don't perform the lockout themselves. They only need to understand the purpose and use of the energy control procedure, not how to execute it.
• All other employees who may simply be in an area where lockout/tagout is in use need to know one thing: never attempt to restart or re-energize equipment that's locked or tagged out.

One nuance worth knowing: employees who exclusively perform normal production work, and whose only contact with servicing happens under normal machine safeguarding, only need to be trained as affected employees, even if the facility's broader program uses tagout elsewhere. Whichever category applies, the employer has to certify that training happened, with each employee's name and the training date on record.

What Do Periodic Inspections Require, and Where Do Employers Get It Wrong?

OSHA requires a periodic inspection of each energy control procedure at least annually, not one inspection covering the whole facility, but one per documented procedure. A few specific requirements trip employers up:

• The inspection must be performed by an authorized employee who is not one of the employees currently using the procedure being inspected: an independent check, not a self-review.
• Where lockout is used, the inspector has to review each authorized employee's responsibilities under that specific procedure with them directly.
• Where tagout is used, that review has to extend to both authorized and affected employees, and must additionally cover the specific tag-limitation training elements the standard requires for tagout programs: a stricter bar than the lockout review.
• The employer must certify the inspection: which machine, the date, which employees were included, and who performed it. Missing or undocumented periodic inspections are one of the most commonly cited failures under this standard.

When Is Retraining Required?

Initial training isn't a one-time event. Retraining is required for authorized and affected employees whenever:

• An employee's job assignment changes.
• A change in machines, equipment, or processes introduces a new hazard.
• The energy control procedure itself changes.
• A periodic inspection reveals deviations or inadequacies in how the procedure is being followed, or the employer has any other reason to believe an employee's knowledge has gaps.

How Do Group Lockout and Shift Changes Work?

Two scenarios get their own specific requirements because a single lock isn't enough to protect multiple people:

• Group lockout. When several employees service the same machine, a primary authorized employee coordinates the group procedure, but each individual employee applies their own personal lock, commonly to a group lockout box or multi-hole hasp. The machine can't be re-energized until every single personal lock has been removed.
• Shift changes. When one shift relieves another mid-servicing, the employer needs procedures ensuring protection doesn't lapse during the handoff, typically by having the incoming shift apply their locks before the outgoing shift removes theirs.

Why This Standard Shows Up So Often in OSHA's Top-10 List

Lockout/Tagout, general industry, ranked fourth on OSHA's list of most frequently cited standards for FY2025, as covered in our guide to what OSHA stands for and its most-cited standards. The pattern behind those citations is consistent: missing machine-specific written procedures, periodic inspections that either didn't happen or weren't documented, and training records that don't distinguish authorized from affected employees.

How EHS Insight Helps

• Permitted Work manages lockout/tagout as a Work Permit type alongside other high-risk activities like hot work and confined space entry, routing each permit through configurable multi-level approvals before work goes active and keeping a closed record for audits.
• Training Management tracks which employees are trained as authorized versus affected, on which equipment, and flags training that's overdue for renewal after a job change or procedure update.
• Compliance Tasks can schedule each machine's annual periodic inspection as a recurring task with reminders, so individual procedures don't quietly go a year or more without review.

These tools help you document and schedule the pieces of a lockout/tagout program. They don't write your machine-specific energy control procedures for you; that still requires a qualified person's hazard assessment for each piece of equipment.

Frequently Asked Questions

What does OSHA 1910.147 require? 29 CFR 1910.147 requires employers to develop written, machine-specific energy control procedures, train employees according to their role (authorized, affected, or other), conduct at least an annual periodic inspection of each procedure, and certify both training and inspections in writing.

What's the difference between lockout and tagout? A lockout device physically restrains an energy-isolating device so it can't be operated. A tagout device is a warning tag only; it doesn't physically prevent re-energization. OSHA requires lockout whenever the isolating device can accept a lock, and permits tagout only when it can't, or when the employer can show tagout provides equivalent protection.

Who needs lockout/tagout training? Authorized employees, who perform the lockout or tagout themselves, need the most detailed training on hazard recognition and isolation methods. Affected employees, who work near the equipment, need to understand the procedure's purpose. All other employees in the area just need to know not to restart locked or tagged equipment.

How often must lockout/tagout procedures be inspected? At least annually, per energy control procedure, not once for the whole facility. The inspection must be performed by an authorized employee not currently using that procedure, and the employer must certify the machine inspected, the date, the employees included, and who performed it.

What happens if minor servicing or cord-and-plug work is treated as exempt when it isn't? Both exceptions are narrow and specific. If the minor servicing exception's conditions (routine, repetitive, integral to production, with effective alternative protection) aren't fully met, or if cord-and-plug equipment isn't unplugged with the plug under the servicing employee's exclusive control, the full lockout/tagout standard applies. Treating routine maintenance as exempt when it doesn't meet these conditions is one of the more common, citable mistakes employers make.