Almost daily I encounter a newcomer to Laser Cleaning who asks the question, "What happens if you run your hand under the laser beam?", followed by the comment "I was watching online where a guy passed his hand under the laser beam and nothing happened".
In recent years, a number of videos have surfaced online where operators demonstrate the apparent safety of laser cleaning systems by passing their hands through the beam of a low-powered, pulsed-wave laser. These demonstrations, while visually convincing, are dangerously misleading. The truth is that not all laser beams are created equal, and what may appear harmless in these videos can be extremely hazardous under different circumstances. The key difference lies in the type of laser being used—particularly, the contrast between pulsed-wave lasers and continuous-wave (CW) lasers.
When it comes to industrial-grade cleaning lasers, particularly continuous-wave (CW) lasers operating at 2000 watts or more, the potential hazards extend far beyond what most people anticipate. Unlike visible light, the near-infrared (IR) light emitted by these lasers penetrates deeply into tissue, causing burns that are not only more painful but also take significantly longer to heal.
The Science Behind IR Burns
Near-infrared light, typically in the wavelength range of 780 nm to 2500 nm, has a unique property: it can penetrate more deeply into human tissue. This deep penetration is due to the relatively low absorption of IR light by water and other components in the skin, allowing the energy to reach deeper layers. When a hand or finger inadvertently passes through a 2000W CW laser beam, the laser’s energy is rapidly absorbed by the tissue, causing extensive damage beneath the skin’s surface.
A Painful Lesson: One Welder’s Experience
In the following images, we see the unfortunate aftermath of an incident where a seasoned welder’s hand passed momentarily through the open beam of a 2000W cleaning laser. The burns are particularly severe at the base of his index finger, where the beam’s intense energy was focused. The first picture shows the initial blistering—a clear indication of the tissue damage beneath the skin.
The blister at the base of the operator's index finger shows the extent of surface damage caused by the laser beam.
In the second image, with the dead skin carefully removed, the depth of the burn becomes apparent. The laser’s IR light penetrated deeply into the underlying tissue, resulting in significant damage that will take time to heal. Unlike superficial burns, the deeper the injury, the more prolonged the recovery process, and the greater the risk of complications such as infection or scarring.
With the dead skin removed, the deep tissue damage is clearly visible, illustrating the severe impact of the near-IR laser beam.
A Welder's Perspective
The injured individual, a welder with many years of experience, described the burn as more painful than any injury he had previously sustained with a traditional acetylene torch. This is particularly telling, as acetylene torches are known for their ability to cause intense heat burns. The welder’s comparison highlights just how severe and painful IR burns can be. Additionally, he noted that the healing process was much slower than what he had experienced with other types of burns. The reason for this lies in the nature of the injury: because the laser’s energy penetrates deeply, the body needs more time to repair the extensive damage.
The Importance of Safety Precautions
This incident underscores the critical importance of stringent safety measures when working with high-power cleaning lasers. Proper training, protective equipment, and strict adherence to safety protocols are essential to prevent such accidents. While lasers are incredibly effective tools for industrial cleaning, their potential to cause severe injury should never be underestimated.
Conclusion
The story of this operators injury serves as a stark reminder of the risks associated with high-power CW lasers. Near-infrared light’s ability to penetrate deeply into tissue makes burns from these lasers especially painful and slow to heal. Whether you’re a seasoned professional or new to working with lasers, prioritizing safety is crucial to avoid the potentially devastating consequences of an accidental exposure.
Stay safe, and always respect the power of the tools you work with.
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