Germicidal Ultraviolet (GUV) Warning Levels

Germicidal ultraviolet (UV) is becoming a more popular disinfectant option because it can inactivate pathogens like viruses and bacteria. However, there are safety warnings that you need to know about before you purchase a UV product.

UV radiation, commonly called UV light, can damage our eyes and our skin if someone is exposed to it. Some products have higher risks than others, so we developed a warning system.

  • A Level 1 warning is the highest level of risk. Level 1 includes products containing germicidal UV or UV-C light.
  • A Level 2 warning carries minimal risk compared to Level 1. Level 2 includes products containing far-UVC light, which studies have shown can be safe around humans, but there are still cautions for certain products.
  • A Level 3 warning has limited risk. Level 3 includes products where UV light is enclosed inside the product. Even though there is no exposure during operation, there may be during installation and maintenance.

⚠ Level 1: High Risk (Germicidal UV or UV-C)

Products containing germicidal UV or UV-C can pose a hazard to the eyes and skin if it’s used improperly, and no one should be nearby when the product is in operation. Germicidal UV includes specific wavelengths of the ultraviolet spectrum, from 200 to 280 nanometers.

Only trained maintenance employees should operate germicidal products to avoid accidental exposure. While there may be no long-term effects from accidental overexposure, a report from the Illuminating Engineering Society (IES) says overexposure can cause severe burns.

Employees operating germicidal UV products should always follow manufacturer instructions and safety guidelines.


⚠ Level 2: Minimal Risk (Far-UVC)

Far-UVC light utilizes only part of the UV-C spectrum, generally from 207 to 222 nanometers.

While scientists have known about the disinfectant qualities of UV-C for decades, far-UVC is a relatively recent topic. Some studies have shown that far-UVC is effective at inactivating germs including viruses and bacteria, while also being safe for humans.

The IES warns that far-UVC may still pose a threat to our corneas depending on the product’s glass envelope, or the outer layer of the light bulb.

It’s always important to read manufacturer warnings before using any product, but especially far-UVC products.

⚠ Level 3: Limited Risk (Enclosed UV)

Manufacturers are also developing products that use the power of germicidal ultraviolet but enclose it within a fixture so there is no direct exposure to humans.

For example, the Cleanse® troffer by Healthé uses broad-spectrum UV inside the fixture to disinfect air as it travels through the troffer. Healthé also developed another product, called the Cleanse® tote, that uses UV enclosed in a portable bag to disinfect small personal items.

Manufacturer guidelines should be strictly followed during installation, use, and maintenance to ensure no exposure to harmful UV.