Hazardous Energy in the Workplace: What It Is & Why It’s So Dangerous

In May 2023, a 3M Company employee suffered fatal injuries at a Wisconsin manufacturing plant after becoming caught in a machine’s rotating rollers. According to the Occupational Safety and Health Administration (OSHA), the incident occurred due to 3M’s failure to follow proper procedures in controlling hazardous energy and implement energy control measures when employees manually threaded powered rollers. 3M was cited for two “willful” safety violations, with a proposed $312,518 penalty. However, it was the employee who ultimately paid the price.

Sadly, this situation is not uncommon.

In workplaces across America, employees are subjected to serious risks from a variety of energy sources. This is particularly true of workers involved in servicing and maintaining machinery and other types of equipment. Hazardous energy—whether electrical, mechanical, hydraulic, pneumatic, chemical, or thermal—can be extremely dangerous when not properly controlled. In fact, improper handling of hazardous energy can lead to severe injuries, including electrocution, amputation and crush injuries, burns, or even death.

What Is Hazardous Energy?

“Hazardous energy” refers to various forms of energy present in machines and equipment that is often harmful when released unexpectedly. This includes energy in electrical circuits, pressurized hydraulic or pneumatic systems, mechanical components, chemical reactions, and thermal processes.

When a machine is turned off, hazardous energy may still be stored within the system, waiting to be released. Without proper precautions and safe energy handling, the effects of this can be catastrophic.

Hazardous energy comes in many forms, such as:

Electrical Energy: Found in live wires, circuits, and equipment
Mechanical Energy: Present in moving parts, springs, and other mechanical components
Hydraulic Energy: Stored in pressurized fluids within hydraulic systems
Pneumatic Energy: Stored in compressed air or gases
Chemical Energy: Released during chemical reactions, such as in batteries or industrial processes
Thermal Energy: Related to heat, such as from steam systems or heated machinery

Hazardous Electrical Energy

Electrical energy is one of the most dangerous forms of hazardous energy. According to OSHA, electrocution is among the “Fatal Four,” one of the top causes of fatalities in industries like construction.

Similarly, the Electrical Safety Foundation reports that 48% of all electrical fatalities between 2011 and 2022 were caused by working on or near energized wires or parts, while 6% were caused by a failure of the lockout/tagout safety devices.

In many occupations, hazardous energy is unavoidable. It is often a necessary part of operating heavy machinery and other equipment, and without it, modern manufacturing, construction, and many other sectors would not exist. The key is to manage this energy safely to prevent accidents.

Types of Injuries Caused by Uncontrolled Hazardous Energy

If not properly controlled, hazardous energy can lead to catastrophic accidents, life-changing injuries, and even fatalities.

Examples include:

Electrocution: From contact with live electrical components
Crushing: From machinery that suddenly moves or releases energy
Burns: From hot surfaces or chemical reactions
Amputations: From moving parts that trap or sever limbs
Fractures and Lacerations: From flying debris or sudden impacts

What Creates Hazardous Energy?

Hazardous energy is generated as a byproduct of the normal operation of machines and equipment across various industries. This energy is inherent in the functioning of these systems and is necessary for tasks such as powering motors, moving mechanical parts, pressurizing fluids, and conducting chemical processes. However, the same energy that enables productivity can become dangerous if not properly controlled.

Active Operation of Machinery

Various forms of energy are required to operate different types of machinery, and these energy sources are continuously at play as long as the machinery is active.

For example, in a manufacturing plant, electrical energy powers conveyor belts, mechanical energy drives moving parts, and thermal energy may be involved in heating processes. When machines are running, energy is being converted from one form to another—such as electrical energy being converted into mechanical motion. This continuous flow and transformation of energy are what keep machines functioning, but they also create the potential for hazards if something goes wrong.

Stored Energy in Deactivated Systems

Even when machines are turned off, they may still harbor dangerous amounts of stored energy. This is especially true for systems that use pressurized fluids or compressed springs.

For example:

Compressed Springs: Springs store mechanical energy when compressed and can release that energy suddenly, causing parts to move unexpectedly.
Pressurized Tanks: Hydraulic or pneumatic systems often contain pressurized fluids or gases. Even when the system is turned off, the stored pressure can be released explosively if a valve is opened, or if a line is disconnected without proper precautions.

Stored energy can pose significant risks during machine maintenance or repair. If not properly de-energized, these systems can suddenly reactivate or release stored energy, endangering workers and anyone else nearby.

Residual Energy in Static Forms

Hazardous energy can also exist in more subtle, static forms, such as:

Residual Heat in Boilers or Furnaces: Even after a system is shut down, residual heat may remain in the equipment. A worker may not realize a surface is still hot, especially if a lot of time has gone by since the machine was shut off.
Residual Pressure in Hydraulic Lines: Hydraulic systems may retain pressure even after being turned off. This pressure can cause components to move or fluids to be ejected with force, leading to crushing injuries or lacerations.

Static energy can be deceptive because the machinery may appear inactive—but the hidden dangers remain. Workers must be aware of these potential hazards and ensure that all energy sources are fully neutralized before starting any work.

Accumulated Energy Due to Equipment Failures

In some cases, hazardous energy can accumulate due to machinery malfunctions or improper operation of equipment.

This can look like:

Electrical Short Circuits: A malfunction in an electrical system can cause energy to build up unexpectedly, leading to sparks, fires, or electrocution.
Mechanical Jams: Machinery that becomes jammed can store mechanical energy as parts are forced into unnatural positions. When the jam is cleared, the stored energy can be released suddenly, causing parts to move with dangerous force.

These situations highlight the importance of routine maintenance and proper safety checks to identify and address potential issues before they result in hazardous energy release. Given the various ways hazardous energy can be created, employers MUST implement stringent energy control procedures to keep their workers safe.

How Can Hazardous Energy Be Controlled?

The most effective way to control hazardous energy is through proper lockout/tagout (LOTO) procedures. LOTO ensures that machinery is properly shut off and cannot be restarted until maintenance is completed. OSHA’s standards for controlling hazardous energy (29 CFR 1910.147) outline detailed steps for safely de-energizing equipment and ensuring it remains de-energized until work is complete.

Industries & Workers Commonly Exposed to Hazardous Energy

Hazardous energy is prevalent in many industries, such as:

Manufacturing: Machinery, assembly lines, and automated systems
Construction: Heavy equipment, power tools, and building systems
Chemical Processing: Industrial reactors, pipelines, and storage tanks
Utilities: Electrical grids, water treatment, and waste management
Transportation: Rail systems, automotive manufacturing, and shipping

Workers in specific roles within these industries are particularly at risk, including:

Craft Workers: Such as electricians, plumbers, and carpenters
Machine Operators: Including those who run and maintain equipment
Maintenance Workers: Responsible for servicing and repairing machinery
Laborers: Any laborer who performs routine tasks that require interaction with machinery or other equipment

Who Is Most at Risk from Hazardous Energy?

While hazardous energy primarily poses risks to workers, nearby communities can be affected by large-scale industrial accidents, such as chemical spills or explosions. Proper safety protocols and emergency response plans are essential to minimize these risks.

States with heavy industrial and manufacturing activities, such as Texas, California, and Ohio, tend to report higher rates of injuries and deaths related to hazardous energy. However, this can vary annually and depends on the enforcement of safety regulations.

How Long Do You Have to Be Exposed to Hazardous Energy for It to Become Dangerous?

The length of exposure to hazardous energy can vary, but it's important to understand that danger can occur in a matter of seconds. Hazardous energy is unpredictable and can cause serious injury or even death in an instant, often without any warning.

For example, a brief contact with live electrical wiring can lead to electrical shock, burns, or may even be fatal, especially if the current is strong. The severity of the injury depends on the voltage, the duration of contact, and the path the electricity takes through the body, but even a split-second exposure can result in irreversible damage.

Similarly, hazardous energy sources like hydraulic systems can release dangerous amounts of pressure very rapidly. A sudden release of hydraulic pressure can crush, sever, or amputate limbs in the blink of an eye, and the force generated can be enough to cause catastrophic damage to the body.

Other forms of hazardous energy, such as mechanical or pneumatic forces, can also be lethal within seconds. Machines with moving parts, for instance, can pinch, shear, or trap body parts, resulting in severe injuries or fatalities before an individual has time to react.

The key takeaway is that hazardous energy doesn't require prolonged exposure to cause harm. Even momentary contact or a brief lapse in safety precautions can have life-threatening consequences.

How Close Does a Worker Have to Be to Hazardous Energy to Be in Danger?

The proximity required to be at risk from hazardous energy can vary significantly depending on the type of energy involved. While some energy sources are only dangerous to those in close physical contact, others can pose a threat from a greater distance.

For example, workers are typically at risk of mechanical and hydraulic hazards when they are near moving parts or pressurized systems. These systems often require workers to be close to machinery or equipment to perform maintenance or setup tasks, increasing the likelihood of injury from entanglement, crushing, or being struck by or caught between moving components.

On the other hand, electrical hazards can be far more unpredictable in terms of proximity. Even when workers are several feet away from live electrical sources, they may still be at risk due to potential arcing, which occurs when electricity jumps across gaps between conductors or to nearby objects. Electrical arcs can travel considerable distances, and, depending on the voltage, workers can be injured from a distance, sometimes even without direct contact. In some cases, electrical hazards, like energized cables or faulty equipment, can create an electrical field that extends far enough to pose a danger to all workers in the vicinity.

Furthermore, certain hazardous energy sources, like electromagnetic fields (EMFs) or radiation, can extend over larger areas, posing risks to workers even when they are not physically close to the source. These invisible dangers may require more advanced monitoring to detect, as they often cannot be seen or felt immediately.

Ultimately, safety comes down to understanding the specific risks of each type of hazardous energy source and maintaining safe distances. It’s essential that workers be educated on how close is too close and for companies to implement safety protocols that minimize exposure to any potential hazards, whether near or far.

Protecting Workers from Hazardous Energy

Hazardous energy is an integral part of many jobs across multiple industries, but it comes with significant risks. Implementing and adhering to strict safety protocols, such as proper lockout/tagout procedures, can ultimately prevent injuries and save lives. Employers must ensure that workers are adequately trained, equipment is properly maintained, and safety procedures are followed. If they don't, workers will inevitably pay the price.