Lockout vs Tagout: What's the Difference?
Lockout and tagout get lumped together as "LOTO," but they are two distinct methods of energy control with different levels of protection. Understanding the difference determines what devices your facility needs, how procedures are written, and whether OSHA considers your program compliant.
Many facility managers assume that lockout and tagout are interchangeable. They're not. And that misunderstanding can create compliance gaps that inspectors will catch, resulting in serious citations.
What Is Lockout?
Lockout is the physical placement of a lock on an energy-isolating device to prevent operation. The lock must be individually keyed and assigned to one authorized employee. A properly installed lockout provides positive physical restraint that cannot be overridden without removing the lock itself.
Under OSHA 1910.147, lockout is the preferred method for controlling dangerous energy. It is the gold standard because it eliminates the possibility of someone accidentally restarting equipment. A worker cannot restart a machine if the padlock is in place, even if they don't know why it's locked. This is why OSHA calls it the "primary" method of energy isolation.
Common lockout devices include:
- Padlocks with unique keying per employee
- Hasps that accept multiple locks for group lockout
- Circuit breaker lockout devices
- Valve lockout devices
- Plug locks for electrical outlets
What Is Tagout?
Tagout is the placement of a warning tag on an energy-isolating device. Tags are warning devices only. They do not provide physical restraint. A tag can be removed by anyone and does not prevent someone from operating the device.
OSHA permits tagout only when the energy-isolating device is not capable of being locked out. This is the key distinction. Tagout is a fallback option, not a preferred method. It relies on training and awareness rather than physical protection. Someone could ignore the tag and restart equipment, which is why additional controls are required when tagout is used alone.
Standard tagout signs include standardized text: "Do Not Operate," "Do Not Start," or "Caution: Equipment Locked Out." Tags must be durable, clearly visible, and include the name of the authorized employee and the date the tag was applied.
Side-by-Side Comparison
| Feature | Lockout | Tagout |
|---|---|---|
| Physical restraint | Yes, prevents operation | No, warning only |
| Can be overridden | No (without key or cutting lock) | Yes (tag can be removed) |
| OSHA preference | Preferred method | Only when lockout not possible |
| Devices used | Padlocks, hasps, circuit breaker lockouts, valve lockouts | Warning tags with standardized text |
| Employee assignment | One lock per authorized employee | One tag per authorized employee |
| Additional protection required | Standard procedures | Must demonstrate equivalent safety |
When Can You Use Tagout Alone?
Under OSHA 1910.147(c)(3)(ii), tagout can be used as the primary method only when the energy-isolating device is not capable of accepting a lockout device. This is a strict requirement. You cannot choose tagout because it's cheaper or easier to implement.
Even when energy-isolating devices cannot accept locks, you must:
- Demonstrate that tagout provides equivalent safety to lockout
- Provide additional training beyond standard lockout training
- Conduct more frequent equipment inspections
- Implement stricter procedural controls and oversight
- Document the justification for using tagout instead of lockout
The reality: modern equipment should be lockout-capable. Manufacturers are expected to design devices that accept locks. If your facility operates older equipment that cannot be locked out, retrofitting is the correct solution. OSHA inspectors will ask why the equipment hasn't been retrofitted, so having a documented retrofit schedule protects your program.
Why Most Facilities Need Both
In practice, most procedures use both a lock and a tag together. The lock provides the physical restraint that makes the equipment safe. The tag identifies who applied the lock and why, serving as communication to other workers. This combined approach is industry standard and is what OSHA inspectors expect to see.
Think of it this way: the lock does the work. The tag tells the story.
It's also important to understand that LOTO placards (the instruction charts mounted on equipment showing lockout steps) serve a different function than tags. Placards are permanent or semi-permanent guides that show workers how to safely isolate energy on that specific piece of equipment. Custom LOTO placards from LOTO Compliance Hub are designed to match your exact equipment and procedures, making it easier for workers to follow the right steps the first time.
Common Mistakes That Get Citations
OSHA inspectors look for these violations regularly:
- Using tagout when lockout devices are available. This is a direct violation. If the equipment can accept a lock, you must use a lock. No exceptions.
- Generic locks not individually keyed. Each authorized employee must have their own lock with their own key. Shared locks and master keys do not comply.
- Tags without standardized information. Tags must include the name of the authorized employee, the date, and clear warning language.
- Not training workers on the difference between locks and tags. Workers need to understand why locks are stronger and what tags cannot do.
- Failing to retrofit old equipment. Inspectors will cite "failure to use preferred method" if equipment can reasonably be retrofitted to accept lockout devices.
- Mixing lockout and tagout without documentation. If you use both, your procedure must clearly state which method applies to which energy type and device.
Ready to Audit Your LOTO Program?
Understanding the difference between lockout and tagout is just the first step. Your facility needs a comprehensive energy control program that matches your equipment, your workforce, and OSHA's requirements.
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