Is Blue Light Disinfection Safe?

The ultraviolet-free and chemical-free Spectral Blue MWHI® disinfection technology uses visible blue light to eliminate microbes, operating at wavelength range of 405 to 450 nanometers. This page presents the safety profile of Spectral Blue MWHI® blue light disinfection — a UV-free and chemical-free technology for safe use in professional settings.

Key Takeaways About the Safety of Blue Light Disinfection

  • Spectral Blue reduces the need for hazardous methods like chemical disinfectants and UVC light, contributing to a safer, healthier workplace.
  • Our blue light disinfection devices are designed for professional use and are completely safe for people and materials when used as intended.
  • The visible blue light wavelengths used (405–450 nm) are safe for skin, even at high exposure levels.
  • Spectral Blue devices are classified using the international Blue Light Hazard standard, with safe viewing distances defined to avoid eye strain.
  • Blue light disinfection does not produce toxic fumes, ozone, or inhalable particles. Blue light is not classified as a carcinogen.

On this page:

How It Works

Blue light kills microbes by activating light-sensitive compounds — porphyrins and flavins — that are naturally found inside microbial cells. When exposed to certain wavelengths (405–450 nm), these compounds produce reactive oxygen species that destroy the microbes from within.

Human cells do not contain these same light-sensitive compounds in a way that causes this reaction. As a result, blue light does not trigger the same effects in human skin, eyes, or tissues — making it safe for human environments when used as intended.

Eye Safety

Bright blue light should not be looked at directly. Like any strong light source, direct, close-range viewing can cause discomfort or even harm the eyes over time. High-intensity blue light can damage retinal cells if a person were to stare at a single LED from very close (20–40 cm) for a prolonged period.

Spectral Blue devices are tested using the internationally recognized Blue Light Hazard (BLH) standard (IEC/EN 62471:2006 and IEC/EN TR 62778:2014). Each device is assigned a risk group rating:

  • RG0: No risk
  • RG1: Low risk
  • RG2: Moderate risk at close range (typically under 30–45 cm)

For example, a device might be classified as RG2 at less than 30 cm, but only RG1 at distances beyond that. These ratings help determine the minimum safe distance for direct viewing.

Importantly, blue light is visible, and our natural reflex is to look away from bright lights. This reflex protects us, but young children or physically impaired individuals may not react quickly — so they should not be left near active devices. Spectral Blue recommends installing devices with timers or motion sensors, so that disinfection runs primarily when rooms are unoccupied and direct viewing is avoided. You can use standard lighting control components for this purpose — no safety-classified equipment is required, as the system emits no ultraviolet (UV) radiation.

Skin Safety

The blue light used in Spectral Blue devices has been shown in clinical studies to have minimal or no harmful effects on human skin cells. Studies examining the effects of various blue light wavelengths (401–470 nm) have found no damage to healthy human tissue under realistic exposure conditions (Leanse et al., 2022).

In controlled skin tests, natural pigmentation (commonly known as tanning) has been observed at doses of 20–80 J/cm² — which corresponds to the cumulative dose from 0.8 to 3 full days of Spectral Blue use. This pigmentation is a natural protective reaction of the skin, not a sign of damage. Its purpose is to help protect skin cells from light-induced stress.

Additional detail from the research by Dr. Mikael Segerstråle (2025) confirms that this pigmentation response is not associated with DNA damage, and that normal skin has sufficient protective mechanisms to handle these light exposures safely.

It’s also worth noting that visible blue light is widely used in medical therapies. It is routinely applied in hospitals to treat newborn jaundice, as well as in acne treatments, wound healing, and other skin therapies. The light wavelengths used in Spectral Blue devices (405 nm and 450 nm) fall well within the range of normal visible light that we are all exposed to daily — from sunlight to artificial lighting.

Air Quality and Inhalation

Unlike ultraviolet disinfection systems, Spectral Blue devices do not produce ozone — a gas that can irritate or damage lung tissue. With UV devices, users may notice a sharp “electric” smell caused by ozone production; this does not occur with blue light.

In addition, Spectral Blue emits no chemical fumes, unlike chlorine-based disinfectants or alcohols, which can pose long-term respiratory risks with repeated exposure. It also avoids the dangers associated with hydrogen peroxide misting, which can leave behind residues and create inhalation hazards, especially in poorly ventilated spaces.

Another often overlooked risk is the generation of microparticles by UV-C light. UV exposure can break down materials — especially plastics — over time, leading to surface degradation and the release of airborne microparticles that may be inhaled. Spectral Blue, which uses only visible light, avoids this issue entirely. Its gentle, non-ionizing light does not break chemical bonds or degrade surfaces, helping maintain both indoor air quality and the integrity of surrounding equipment.

In fact, by inactivating airborne microbes such as mold spores and bacteria, blue light disinfection can even help improve air quality — reducing symptoms related to microbial contamination in indoor environments.

Residues and Material Compatibility

Blue light disinfection is clean — it does not leave chemical residues on surfaces. This makes it especially suitable for food production, laboratories, and healthcare environments.

Because it is part of the visible spectrum, blue light is non-corrosive and non-abrasive. It does not degrade plastics, polymers, or delicate equipment surfaces like UV light or chemical disinfectants can. While some plastics with specific impurities may slowly react to 405 nm light over long exposure periods, such cases are rare. If needed, materials can be tested by exposing a sample to the light at close range.

In Summary

Spectral Blue’s multi-wavelength blue light is an effective and safe disinfection method for professional environments. It works by targeting microbes — not human cells — and avoids many of the health and material risks associated with traditional disinfection methods.

Scientific References and Further Resources:

Segerstråle, M. (2025). Effects of Blue Light. University of Helsinki. (Internal summary)

Leanse, L.G., dos Anjos, C., Mushtaq, S., & Dai, T. (2022). Antimicrobial blue light: A ‘Magic Bullet’ for the 21st century and beyond. Advanced Drug Delivery Reviews, 180, 114057. https://doi.org/10.1016/j.addr.2021.114057

Blue Light Hazard Standard: IEC/EN 62471:2006 and IEC/EN TR 62778:2014