ELECTROCUTION AND ELECTRICAL FATALITIES BASIC INFORMATION

The term electrocution refers to an electrical event with electrical current exposure that results in death. The implication is that the current flow has caused an electrical shock with subsequent death.

“Electrical accident fatality” is a general use phrase seen in news reports meaning either electrocution, or death resulting at the time of the electrical accident. This phrase may include fatalities associated shock or other forms of energy released at the time of the electrical accident, in particular those causing physical changes including burns, blast effects, and radiation damage.

“Electrical injury mortality” is a medical statistics phrase which suggests that persons who were injured in an electrical accident lived long enough to receive medical care for their injuries, but the medical care was not followed by survival.

It’s important to appreciate that an electrical event can produce a fatality or injury even when there is no electrical current flow to the victim or electrical shock. This might be the situation, for example, when a victim is caught in an electrical ignition fire, explosion, or blast.

In this type of scenario, the “root cause” of the accident is electrical, but the mechanism of death or injury is from thermal, acoustic, radiation, or blast exposure related to electrothermal chemical (ETC) combustion.

Another way employees can be killed or injured after an electrical event is that they are surprised by an energized source, either through a spark, like a static “zap” to exposed skin, or through a noise, like a sharp “gunshot” type sound close to the head.

The surprise can lead to an unintended body movement which might be characterized as a “startle response.” If the startle occurs at the top of a ladder or scaffold, the direct mechanism of death or injury can be through a fall.

If the startle occurs in proximity to other energized equipment that is moving, the direct mechanism of death or injury can be with a body part being caught in or by the moving equipment.

Fatal and non-fatal electrical incidents share three characteristics:

1. The unintentional exposure of employees to electrical energy;
2. Compliance failure in at least one aspect of electrical design, installation, policies, procedures, practices, or personal protection; and
3. Energy transfer to exposed employees in some combination of electrical, thermal, radiation, acoustic (pressure), mechanical, light, kinetic, or potential energy.

What is the difference between fatal and non-fatal electrical incidents? The answer depends in part on whether the question is asked hypothetically, like in a “what if ” planning scenario; or whether the question is asked retrospectively after a traumatic accident has occurred.

Hypothetically, based on human physical and biological characteristics, we know that a fatal electrical event transfers a greater amount of energy to its victim than a non-fatal situation. This knowledge about the fatal risk of energy transfer underlies the use of equipment designs (for example, required doors, specified space clearances, venting systems on equipment to discharge combustion products, “umbilical corded” controls, infrared monitoring ports for doors closed heat monitoring) and barrier protection (such as PPE, including leather gloves, flash suits, safety glasses, face shields, long sticks, extended handles, and flame resistant clothing).

By reducing the amount of possible energy transfer during an unintentional electrical exposure, strategies including equipment design and barrier protection can increase the likelihood of survival after an electrical incident.

Retrospectively, if two people are present in an electrical incident when one dies and the other survives, the difference in survival may come down to nuances in the victims’ innate individual differences and their spatial and temporal relationship to the electrical hazard at the time of the energy release, transformation, and transfer. Medical and legal privacy protections tend to reduce accessibility to accident details, so systematic information is lacking about how various scenarios unfold.

Generally, there is a lethal exposure “dose” for different forms of energy that can result in death. When multiple forms of energy are involved in an electrical event, multiple lethal or sublethal doses of energy may flow from the event, transformed from the electrical hazard source, and transferred to nearby employees may result in highly variable damage to the body.