An arc flash can cause thermal burns, blast-wave trauma, eye damage, respiratory injury, nerve damage, and lasting psychological harm. These events release temperatures up to 36,000°F and generate pressure waves strong enough to throw a person across a room. In 2023, 147 workers in the United States died from exposure to electricity or electric arcs, a figure consistent with the ten-year average reported by the National Fire Protection Association.
Thermal Burns
The most immediate and common injury from an arc flash is a severe burn. At 36,000°F, an arc flash is roughly four times hotter than the surface of the sun, and that heat radiates outward in a fraction of a second. Exposed skin and clothing can ignite almost instantly. Burns range from superficial reddening to full-thickness destruction of skin and underlying tissue, depending on how close you are to the arc and how long the event lasts.
Burn severity in an arc flash is measured by something called incident energy, expressed in calories per square centimeter. Protective clothing is rated against this scale: low-risk tasks involve energy levels up to about 4 cal/cm², while severe arc events can exceed 40 cal/cm². That rating represents the threshold at which the fabric can no longer prevent a second-degree burn. Without proper protection, even a brief flash at moderate energy levels is enough to cause blistering and permanent scarring. At higher levels, burns penetrate deep into muscle and bone, requiring skin grafts and long-term wound care.
Blast-Wave and Impact Injuries
An arc flash doesn’t just produce heat. It also causes an explosive expansion of air and vaporized metal, creating a blast wave that can reach 2,000 pounds per square foot. For context, eardrum rupture can occur at around 720 lbs/sq ft, and lung damage becomes likely at about 1,728 lbs/sq ft. That means anyone standing near the arc is at risk for ruptured eardrums, collapsed lungs, and damage to organs like the spleen, liver, and intestines.
The blast can also launch a 170-pound person across a room at over 100 miles per hour. These secondary impacts cause broken bones, traumatic brain injuries, and spinal damage. Molten metal and equipment fragments become shrapnel traveling at speeds up to 700 miles per hour, fast enough to penetrate the body. Even workers wearing proper protective equipment can sustain serious injuries from the pressure wave and flying debris alone. Noise from the blast often exceeds 140 decibels, well above the threshold for immediate hearing damage.
Eye and Vision Damage
An arc flash emits intense radiation across the spectrum, from ultraviolet through visible light to infrared. This radiation can damage every structure of the eye. The most common injury is photokeratitis, sometimes called “welder’s eye,” a painful inflammation of the cornea caused by ultraviolet exposure. It typically feels like sand in the eyes and can develop hours after the event, even from a brief, unprotected glance at the arc.
More serious exposures can cause cataracts over time or direct damage to the retina. When intense visible and infrared light (in the 400 to 1,400 nanometer range) enters the eye, the lens focuses it onto the macula, the part of the retina responsible for sharp central vision. This concentrated energy causes thermal or photochemical damage to the light-sensitive cells there. The photochemical reaction releases toxic byproducts that destroy surrounding tissue, and the damage can be permanent. Retinal injury from a brief arc exposure can occur without any pain at the time, making it easy to underestimate the severity until vision loss becomes apparent.
Respiratory and Inhalation Injuries
When an arc flash vaporizes copper conductors and other metals, it produces a cloud of metallic fumes and superheated gases. Inhaling these fumes can irritate the nose, throat, and lungs, causing coughing, wheezing, and shortness of breath. In more severe exposures, the heat and toxic particles can trigger bronchitis, chemical pneumonia, or pulmonary edema, a dangerous buildup of fluid in the lungs. Copper oxide, zinc, and magnesium fumes are among the most common irritants released during electrical arc events. The superheated air itself can also burn the airway, causing swelling that restricts breathing in the critical minutes after the incident.
Neurological Effects
Electrical injuries, including arc flash events where current passes through the body, carry a significant risk of lasting nerve damage. A large register-based study found that electrical injury survivors had increased rates of seizures, involuntary movements, headaches, migraines, and vertigo in the years following their injury. Peripheral nerve damage was especially common, with mononeuropathy (damage to a single nerve, usually in an arm or leg) being the most frequent diagnosis. This makes sense because the limbs are typically where electrical current enters or exits the body.
Nerve root and plexus disorders, which cause pain, weakness, or numbness radiating along a nerve’s path, also occurred at higher rates. Disturbances in skin sensation, including tingling, burning, or numbness, were common peripheral complaints. Most of these neurological conditions appeared within the first six months after injury, but for some diagnoses, symptoms didn’t emerge until up to five years later. That delayed onset can make it difficult to connect new neurological symptoms to the original arc flash event.
Hearing Loss
The explosive pressure wave from an arc blast routinely exceeds 140 decibels, a level that causes immediate pain and can rupture the eardrum in a single exposure. Even when the eardrum stays intact, the sudden pressure spike can damage the tiny bones and sensory cells of the inner ear, leading to permanent hearing loss or chronic tinnitus. Because the blast happens in milliseconds, there is no time to react or cover your ears. Hearing damage from arc flash events is often permanent and bilateral, affecting both ears simultaneously.
Psychological Trauma
Surviving an arc flash, or witnessing one, can leave psychological injuries that persist long after physical wounds heal. The event is sudden, violent, and life-threatening, a combination that puts survivors at elevated risk for post-traumatic stress disorder. Common symptoms include intrusive flashbacks and nightmares about the event, emotional numbness, difficulty sleeping, and an exaggerated startle response. Some survivors develop panic attacks with physical symptoms like racing heart, sweating, and dizziness.
Chronic pain from burn injuries and nerve damage can compound the psychological burden, contributing to depression, social withdrawal, and substance use. Many survivors report losing trust in workplace safety, difficulty returning to electrical work, and strain on personal relationships. These psychological effects can emerge weeks or months after the incident, and symptoms lasting beyond one month may indicate PTSD that benefits from professional treatment. The physical disfigurement that sometimes follows severe burns adds another layer of emotional difficulty, affecting self-image and daily social interactions.
How Distance and Duration Shape Severity
The severity of every arc flash injury depends on three variables: how close you are to the arc, how long the arc persists, and what you’re wearing. A worker standing two feet from a high-energy arc in a t-shirt faces a fundamentally different outcome than one standing ten feet away in rated protective gear. Blast pressure drops rapidly with distance, but even at several feet, the force can still cause falls, impact injuries, and hearing damage. Thermal energy follows the same pattern: incident energy decreases with distance, but the initial output can be so extreme that even workers at the edge of the flash boundary sustain second-degree burns.
Protective clothing rated to the appropriate calorie level prevents or reduces thermal burns, but it does not eliminate the risk of blast injuries, hearing loss, or eye damage. Face shields with appropriate arc ratings protect against both thermal and optical injury, while hearing protection is rarely worn during electrical work despite the known risk. The combination of proper protective equipment, safe working distances, and engineering controls that limit arc duration is what separates a survivable incident from a fatal one.