LOTO 4.0: Will U.S. OSHA Update Its 1989 Lockout/Tagout Standard?

When the U.S. Occupational Safety and Health Administration (OSHA) issued its lockout/tagout standard in 1989 (29 C.F.R. § 1910.147), the agency was regulating an industrial landscape dominated by physical disconnects, breakers, valves, and switches. 

The standard's premise was straightforward: if a worker needed to service machinery, the safest approach was to isolate hazardous energy physically and visibly – cut the power before servicing. A lock on a disconnect switch was a simple, tangible assurance that the machine could not unexpectedly spring back to life.

As intuitive as that is, workplaces have already started to outgrow it. It's time for the standard to embrace the Fourth Industrial Revolution: Industry 4.0. According to the U.S. Department of Labor’s latest regulatory agenda, OSHA plans to propose an update to the lockout/tagout standard in November 2026. The agency says that advances on the shop floor, driven by smart manufacturing, connectivity, and cyber-physical systems, have increasingly come into conflict with a rule written before technology - i.e., the Internet of Things - became commonplace. 

In its statement of need, OSHA notes that national consensus standards have evolved, and that other countries have increasingly recognized the use of computer-based controls as part of hazardous-energy management systems. The agency argues that modernization could improve safety while also increasing operational efficiency and reducing regulatory burdens.

The resulting rulemaking may become one of the most consequential workplace safety debates of the next several years. Can software, sensors, and sophisticated control systems protect workers as well as an old-fashioned mechanical lock?

Back to the Future

The central challenge confronting OSHA is that the current rule rests on assumptions formed during a different technological era.

Under existing requirements, control-circuit devices generally do not qualify as energy-isolating devices (EID). The standard was written on the premise that control systems could fail, become energized unexpectedly, or otherwise prove unreliable compared with physical isolation. In fact, the item on OSHA's regulatory agenda notes that the current definition of EIDs “excludes push buttons, selector switches, and other control-circuit-type devices.”

No regulator or lawmaker in the 1980s could have anticipated modern manufacturing facilities, which rely on programmable logic controllers, safety-rated automation systems, robotics, interlocks, laser scanners, and presence-sensing technologies that can detect workers and stop hazardous motion within fractions of a second.

The American Society of Safety Professionals (ASSP) argues that consensus standards have evolved to reflect those technological realities. In a statement to 3E, the organization noted that ANSI/ASSP Z244.1 has steadily expanded beyond its original focus on mechanical lockout. Recent revisions formally recognize alternative methods, incorporate risk assessment requirements, and address the use of safety-rated automation and control-reliable technologies. The 2024 revision went further still, elevating alternative hazardous energy control methods to a status coequal with traditional lockout procedures while also incorporating cybersecurity considerations.

For ASSP, the key principle is not whether a protective measure resembles a traditional lockout procedure. Rather, it is whether the chosen method can demonstrably reduce risk to an equivalent level. 

“ASSP hopes OSHA's [rulemaking] will prioritize risk management to determine the most appropriate control of hazardous energy,” said the society's spokesperson. “It should be a systematic, typically qualitative process that identifies tasks and hazards, assesses both initial and residual risk, implements risk reduction measures, validates the effectiveness of solutions, and documents the process.”

A 'Frozen' Standard

That theme surfaced prominently during a May hearing before the House Education and Workforce Committee’s Subcommittee on Workforce Protections.

Melissa Peters, a shareholder at Ogletree Deakins and a former attorney with California’s Division of Occupational Safety and Health (Cal/OSHA), told lawmakers that the protocol has become a textbook example of regulatory lag. “The lockout/tagout standard is frozen in 1989 technology,” she told the subcommittee.

Peters listed a number of new technologies unaccounted for: light curtains, safety laser scanners, trapped-key interlocks, and safety-rated monitored stops. In many cases, she argued, these systems are capable of detecting workers and placing machinery in a verified safe condition faster and more reliably than a worker following a series of manual steps. Worse, some mechanical lockout procedures can encourage workers to take shortcuts during routine interventions such as clearing jams or performing minor adjustments. Many serious incidents occur in the gray area between full lockout and normal production, she told the subcommittee, where workers feel pressure to complete a quick task without shutting an entire system down. 

Lawrence Halprin, a partner at Keller & Heckman who has spent decades working on lockout/tagout issues, agreed, telling 3E that updated, mandatory energy control protocols - automated, traditional, or some combination of both - were necessary. A proposed update from OSHA is “long overdue,” he claimed. “The current standard was outdated at the time it was adopted.”

According to Halprin, OSHA had, in 1989, only a limited understanding of automated control systems and what safety engineers now call “functional safety,” systems designed to detect dangerous conditions and automatically place equipment into a safe state.

A key turning point came in the Sixth Circuit’s 1996 decision in Reich v. General Motors Corp. Delco Chassis Division. The court concluded that lockout procedures were not required when employers could demonstrate that automated systems eliminated the possibility of unexpected energization or startup. Ever since, said Halprin, OSHA has struggled with how to enforce the standard consistently in facilities using sophisticated automated controls.

'Computers are Smart, But People Aren't'

Adele Abrams, an OSHA attorney and certified safety professional who has handled hundreds of workplace fatality investigations, generally agrees: OSHA must revisit the standard. She told 3E this month that “the technology has certainly outstripped the current rule,” and that employers should not have to pursue variances merely to use well-established protective technologies such as laser guarding systems.

At the same time, she said, many safety professionals remain wary of relying too heavily on computerized controls. She herself recalled a near-fatal arc-flash incident involving a computer-based lockout system. A communication breakdown between a contractor and a host employer resulted in a shutdown procedure being misunderstood. When a crew powered down a computer system, equipment that workers believed had been isolated unexpectedly reenergized while an electrician was still performing work.

“He nearly died,” Abrams said. “Computers are smart, but people aren’t.”