Laser Classes and Safety: Class 1 to 4 Explained

Laser classes and safety rules are defined by IEC 60825-1, which sorts every laser product into hazard classes based on the harm its accessible radiation could cause. For hospital laser safety officers and biomedical engineers, the class printed on the label tells you what controls are expected in the room, what eyewear is needed and who may operate the device. This article explains the classes in plain language.

How IEC 60825-1 classifies lasers

The standard compares the radiation that a person could access during normal use with accessible emission limits. The result is a class from 1 (lowest hazard) to 4 (highest). The classification depends on wavelength, power or energy, pulse duration and beam divergence, and it is assigned by the manufacturer, who must label the product.

Always read the label and the user manual rather than assuming. Laser products can contain an embedded higher-class laser that is enclosed so that the product as a whole is Class 1, and the class of the accessible beam may change when covers are opened or optional accessories are fitted.

Class 1, 1M, 2, 2M and 3R

Class 1 lasers are safe under reasonable foreseeable conditions of use, including viewing with the naked eye; Class 1M is safe unless viewed with magnifying optics such as binoculars. Class 2 covers visible lasers whose power is low enough that the blink reflex gives protection, and 2M adds the optical-instrument caveat. Class 3R lasers have a reduced but real risk and need care with direct viewing.

Some medical devices are Class 1 by design. For instance, the manufacturer lists the CETUS NanoLaser as Laser Class 1, so no laser safety goggles are required with it, while its internal laser stays enclosed. Verify the claim in the manual for your model.

Class 3B and Class 4 lasers in the clinic

Class 3B lasers are hazardous to the eye with direct or specular exposure; diffuse reflections are normally safe. A slit-lamp SLT laser such as the CITO 532 is listed as Class 3B and has a permanent physician protection filter, but those present should still follow the facility's rules.

Class 4 lasers are those above the Class 3B limits. Their direct and diffusely scattered beams can damage eyes and skin, and they can ignite materials. Surgical CO2 lasers, high-power diodes and many photocoagulators fall here; the manufacturer lists the CLASSIC 514 retinal laser as Class 4. For room requirements see laser operating room requirements.

What each class means for controls and training

For Class 3B and 4 devices, typical controls include a defined controlled area, warning signs, key switch and interlocks, an emission indicator, trained and authorised operators, written local rules and a laser safety officer. Eyewear must match wavelength and optical density; see medical laser safety eyewear.

Medical lasers also fall under the particular standard for laser equipment in medical use, IEC 60601-2-22, in addition to the general IEC 60601-1. The role and duties of the person who manages this are described in the medical laser safety officer.

Practical checklist for your department

Make a register of every laser with its class, wavelength, power, location and the eyewear required. Check that labels are legible, that warning signs match the class and that new staff are trained before first use. Review the register after any purchase or service visit.

Confirm regulatory and licensing requirements for your facility with the UAE authorities that apply to you. If you plan new equipment and need help with a safety plan, ask Beckfinity's specialists.

Frequently asked questions

What laser class are surgical lasers?

Surgical lasers are normally Class 4, meaning direct and scattered radiation can injure eyes and skin and may start fires.

What is the difference between Class 3B and Class 4?

Class 3B is hazardous with direct or specular viewing but typically not diffuse reflection. Class 4 exceeds the 3B limits, so even diffuse reflections can be dangerous and there is a fire risk.

Does a Class 1 laser need goggles?

Not in normal use if the product is truly Class 1 as a whole, but follow the manufacturer's manual, especially during service when covers are open.

Who assigns the laser class?

The manufacturer classifies the product according to IEC 60825-1 and labels it accordingly.

Medical lasers

Laser Classes and Safety Controls: What Each Hazard Class Requires