The hazard is stored energy
The lockout/tagout standard, 29 CFR 1910.147, covers servicing and maintenance of machines and equipment where unexpected energizing, startup, or release of stored energy could hurt someone. In the oilfield that means mud pumps, cement units, compressors, generators, winches, cranes, and pressurized lines. OSHA's fact sheet on the standard is blunt about the scale: about three million workers service equipment, compliance prevents an estimated 120 fatalities and 50,000 injuries each year, and workers injured by hazardous energy lose an average of 24 workdays recovering.
The program elements
The standard requires an energy control program: documented procedures for each piece of equipment, locks and tags that identify the worker who applied them, training for authorized and affected employees, and a rule that only the worker who applied a lock may remove it, with a narrow exception for shift and personnel changes. New or overhauled equipment must be capable of being locked out. Procedures must be inspected at least annually, and the inspection has to be performed by an authorized employee other than the one using the procedure.
Where oilfield maintenance breaks
The classic oilfield failures are familiar: a pump tagged but not locked because the lock was in the truck, a crew that treats the tag as the control, group lockout where the second shift untags equipment the first shift left mid-job, and pressure vessels worked on while still holding pressure because bleeding them down would cost a day. OSHA cited lockout/tagout more than 2,400 times in fiscal 2024, the fifth most-cited standard in the agency's top ten. Every one of those citations started with the same sentence: the energy was not controlled.
Lockout/tagout is the maintenance counterpart to MRO discipline and the direct enemy of unplanned downtime: the procedure takes ten minutes and the shortcut takes a life. The work order, the lock register, and the annual inspection are records that belong in the same system as the PM schedule. If maintenance runs on memory and the lock register is a clipboard, an operations audit will show where the energy control program is a paper program.