Critical elements of an effective lockout/tagout program

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Keep these factors in mind when developing your company’s lockout/tagout program.

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The lockout/tagout standard, 29 CFR 1910.147, is arguably the best Occupational Safety and Health Administration (OSHA) standard ever written. For the price of a lock and tag, an employee can be confident he or she is protected from the sudden release of hazardous energy while performing maintenance, cleaning or servicing activities on equipment. When performed correctly, lockout/tagout is extremely beneficial; however, when performed incorrectly, serious injuries and fatalities may occur.

During the last 15 years, I’ve had the opportunity to review lockout/tagout programs for a broad range of industries, from steel and paper to chemical. Listed below are critical elements necessary to ensure an effective lockout/tagout program.

1. Servicing and maintenance activities versus lockout/tagout

I recently observed a machinist reprogramming a CNC machine with his arms entirely inside the machine. When questioned about lockout, the machinist stated: “This is a normal production operation—lockout is not required.”

This is a very unsafe practice; a multiple amputation could occur if the machine were to become energized suddenly.

Do your employees follow lockout/tagout when changing the grinding wheel on an abrasive grinder, adjusting the belt speed on a drill press or changing a light ballast on a fluorescent light? Lockout procedures must clearly define what constitutes normal production operations versus when equipment must be locked out.

2. Identifying all energy sources: equipment-specific procedures

To ensure employee safety, it is imperative that all potential energy sources are identified. Employees typically apply locks and tags on the main electrical disconnect; however, additional energy sources, such as thermal, hydraulic, pneumatic, radioactive, gravity or chemical energy, may exist on equipment. OSHA requires equipment-specific lockout procedures for equipment containing two or more energy sources. (See 29 CFR 1910.147[c][4].)

3. Correct identification of energy-isolating devices

When isolating energy sources, employees frequently lockout control-circuit-type devices, such as power switches, emergency stops, interlocks and three-way selector switches. This is a very unsafe practice; control circuits do not isolate the flow of electrical energy to a piece of equipment.

To achieve proper equipment isolation, an energy-isolating device, such as an electrical circuit breaker or main electrical disconnect, must be locked out. For OSHA’s explanation of an energy-isolating device, refer to 29 CFR 1910.147 (b).

Lockout/tagout ensures employee protection while performing servicing, maintenance and other activities on equipment.

4. Protection of all employees

Lockout/tagout ensures employee protection while performing servicing, maintenance and other activities on equipment. However, lockout/tagout is seriously compromised when more than one employee is working under the same lockout/tagout device. An employee inadvertently could remove his or her locks and tags, seriously exposing unprotected employees. The best practice is for each employee to apply his or her personal lockout/tagout devices to each energy-isolating device. For complex jobs involving several employees and multiple energy sources, group lockout may be used.

5. Correct selection and use of locks

While performing lockout audits for clients, I commonly observe the misuse of lockout locks and tags. For instance, I once observed 300 employees using identically keyed locks—employees could remove one another’s locks. In another case, a supervisor had the duplicate keys for all her employees’ locks.

Another problem is securing tool cribs and personal lockers with lockout locks.

The best practice is to use uniquely keyed locks that come with only one key. Additionally, lockout and tagout devices must be standardized (See 29 CFR 1910.147[c][5][ii].) and must not be used for any other purpose.

6. Verification of isolation: lock-tag-try

Verification of isolation must be performed by every employee prior to commencing servicing and maintenance activities. Many companies refer to their lockout program as “Lock-Tag-Try.” In most cases, isolation may be verified by attempting to operate the machine. (See 29 CFR 1910.147 [d][6] and 29 CFR 1910.333 [b][2][iv].)

7. Training all employees

Most companies train employees who apply locks and tags to equipment (authorized employees). However, equipment operators and employees who may be in proximity to equipment that is locked out (affected employees) also must be trained in lockout/tagout. In addition, all other employees need to receive awareness training on lockout/tagout and the prohibition against removing lockout locks and tags from energy-isolating devices or attempting to operate locked out equipment. (See 29 CFR 1910.147 [c][7][i].)

8. Periodic (annual) inspection of lockout program

29 CFR 1910.147 (c)(6)(i) requires employers to conduct an annual review of their lockout/tagout programs to verify program effectiveness. Each equipment-specific lockout procedure should be field reviewed to ensure lockout/tagout is being performed correctly. Deficiencies must be corrected through revised procedures, training or both.

W. Jon Wallace, CSP, MBA, is a safety consultant with nearly 30 years of occupational safety experience. He also is an adjunct assistant professor at The University of North Carolina at Chapel Hill. He can be reached by email at or by phone at 919-933-5548. This piece is reprinted from the Workplace Safety website,, with his permission. Wallace founded Workplace Safety in 2002.