The Definition of Laser Safety

Definition of Laser Safety

Laser safety is the set of engineering controls, work practices, protective equipment and training used to protect people from injuries caused by laser beams. Lasers produce a narrow, concentrated beam of light that can damage the eyes and skin, and high-power lasers can also start fires. Even a brief reflection from a shiny surface can cause permanent eye damage.

Lasers are used in manufacturing for cutting, welding, marking and measurement, in construction for leveling and alignment, in healthcare for surgery and cosmetic treatments, in research labs, telecommunications and entertainment. The level of control needed depends on the laser's hazard class.

In the United States, the FDA's Center for Devices and Radiological Health regulates laser product manufacturers, and the ANSI Z136 series of standards, especially ANSI Z136.1, sets out how users should control laser hazards. OSHA has limited laser-specific rules, such as 29 CFR 1926.54 for construction, and relies on ANSI Z136 and the General Duty Clause. Internationally, IEC 60825-1 is the main standard for laser classification.

Laser Hazard Classes

• Class 1 and 1M: safe under normal use. Class 1M may be hazardous if viewed with magnifying optics such as binoculars.
• Class 2 and 2M: low-power visible lasers. The natural blink reflex usually protects the eye, but staring into the beam can cause injury.
• Class 3R: low risk, but direct viewing of the beam can injure the eye. Many laser pointers and alignment lasers fall here.
• Class 3B: direct or reflected beam viewing can cause eye injury. Diffuse reflections are usually not hazardous.
• Class 4: high-power lasers that can injure the eye and skin through direct, reflected and even diffuse reflections, and can ignite materials. Industrial cutting and welding lasers are usually Class 4.

Laser Safety Controls

Engineering controls

• Enclose the beam path and the work area, especially for Class 3B and Class 4 lasers.
• Use safety interlocks on doors and access panels that shut off the laser when opened.
• Fit key switches, emergency stops and beam shutters.
• Use non-reflective surfaces and beam stops to block stray reflections.
• Capture fumes from laser cutting and welding with local exhaust ventilation, since laser-generated air contaminants can be toxic.

Administrative controls

• Appoint a Laser Safety Officer (LSO) for Class 3B and Class 4 lasers, as ANSI Z136.1 recommends.
• Define a nominal hazard zone where exposure could exceed safe limits and control access to it.
• Post warning signs and labels at entrances to laser areas.
• Write standard operating procedures for operation, alignment and maintenance. Beam alignment is when many injuries happen.
• Train all operators and people working nearby.

Personal protective equipment

Laser safety eyewear must be selected for the specific wavelength and power of the laser, using the optical density (OD) rating on the eyewear. General safety glasses do not protect against laser beams. Eyewear should be inspected regularly and replaced if damaged. Skin protection may also be needed for high-power ultraviolet and infrared lasers. See eye protection for more.

Example of Laser Safety

A metal fabrication shop installed a new Class 4 fiber laser cutting machine. The machine came fully enclosed with interlocked doors, so it operated as a Class 1 product during normal cutting. However, the maintenance team sometimes bypassed the interlocks during beam alignment and lens changes.

The company appointed a trained Laser Safety Officer, who wrote a service procedure requiring the area to be cordoned off, warning signs posted and wavelength-specific eyewear with the correct optical density worn during any work with the enclosure open. Interlock bypass keys were controlled by the LSO, and maintenance technicians completed laser safety training before servicing the machine.

Frequently Asked Questions: Laser Safety

Can ordinary safety glasses protect against lasers?

No. Laser eyewear must match the laser's wavelength and have a sufficient optical density. Ordinary safety glasses or sunglasses do not provide this protection.

What is a Laser Safety Officer?

A Laser Safety Officer is a person with the authority and training to oversee laser hazards, approve procedures, define hazard zones and make sure controls are in place. ANSI Z136.1 calls for an LSO wherever Class 3B or Class 4 lasers are used.

Are construction laser levels dangerous?

Most construction laser levels are Class 2 or 3R. They are low risk but can still injure the eye if someone stares into the beam, so workers should never look directly into the beam or point it at others.