Lasers are powerful tools that are often used in labs requiring intense light sources to study or manipulate different kinds of materials. Due to the wavelengths of the light and the power of the laser beams, lasers can present potential hazards to lab staff. Especially for non-visible lasers, these unseen risks can easily be overlooked or underappreciated. Both federal Occupational Safety and Health Administration (OSHA) and state-level OSHA programs recognize the ANSI Z136.1, Safe Use of Lasers standards as a means to demonstrate laser safety compliance. Here are seven tips to help keep your lab safe when using high-power lasers:
Laser hazards
It is vital to evaluate the hazards presented by the lab laser systems. The direct hazards from laser beam exposure in the lab are eye and skin damage. Laser light can cause severe damage to the eye, including retinal burns, cataracts, and blindness. Even indirect reflections can be sufficiently intense to cause significant damage. High-power lasers can also generate severe acute burns on exposed skin. Lasers can also present non-beam risks, such as electrical shock and toxic chemical inhalation risk from laser-generated air contaminants.
Laser types and classifications
Lasers are categorized into four broad classes based on their power:
- Class 1 lasers are completely safe under normal operation. This includes Class 1M, and Class 1 products.
- Class 2 lasers have low power and are only hazardous when observed for prolonged periods or directly. This includes Class 2 (visible 1 mW) and Class 2 M.
- Class 3 lasers are moderate to high risk to the eyes, and specular reflections can cause damage. Class 3 is divided into Class 3R (the laser pointer level) and Class 3B 5- 500 mWatts.
- Class 4 lasers are high power and high risk, and even scattered reflections can cause damage. Class 4 has no upper power limit.
The extent of laser risk is also dependent on the wavelength, which determines where the energy is absorbed. Lasers can produce a wide range of wavelengths, from ultraviolet to visible, and into the infrared.
Beam path and exposure risk
To mitigate the risks associated with the laser, it is essential to understand the beam’s path. Laser beams will travel in straight lines between optics, but all reflections from each optical surface must be understood and contained. It is best practice to:
- Shorten the beam path as much as possible
- Remove any unnecessary optical elements
- Ensure all optical elements are rated for the power and wavelength of the laser
- Safely block or capture all reflections and the main beam at the end of the beam path
- Understand the function of optical components, from beam splitters to rotators to nonlinear optics
Nominal hazard zone
The ANSI standard defines the nominal hazard zone (NHZ) to be the area around the laser source that contains direct and any reflected laser light that can be hazardous to staff. Anyone working within the NHZ must wear appropriate personal protective equipment (PPE), especially laser protective eyewear chosen for the power and wavelength of the laser source. The NHZ can be reduced by beam containment.
All staff members are required to understand the location of the NHZ, with appropriate signage and barriers in place. No one should enter the NHZ accidentally or without the appropriate training, PPE, or supervision.
Containment methods
Most laser-based equipment used in laboratories encloses the laser hazard. Laser beams can be contained by erecting barriers that completely absorb direct, reflected, and scattered laser light. A typical approach is to erect non-reflecting, often black, metal barriers around the beam path. It is essential that these barriers contain all reflected and scattered light; therefore, they may need to block reflections that occur in all directions, including those going up and down, as well as in the plane of the laser beam. Diffuse visible light, although not an eye hazard, can create a perception of risk and should be addressed. Containing high-power laser beams may require more robust materials that can absorb high-power beams for extended periods of time.
Lab Quality Management Certificate
The Lab Quality Management certificate is more than training—it’s a professional advantage.
Gain critical skills and IACET-approved CEUs that make a measurable difference.
It is important to remember that the risk mitigation provided by the enclosures can change when service or maintenance is performed. The removal or bypassing of enclosures and interlocks can expose lab staff and service engineers to the full range of laser hazards.
Laser safety officer
The laser safety officer (LSO) is responsible for all aspects of lab laser safety. These individuals require appropriate training and must have a comprehensive understanding of the lasers used in the lab. An LSO is required by OSHA for organizations using class 3B and class 4 lasers. Key responsibilities include:
- Hazard evaluation
- Establishing control measures
- Approving procedures and modifications for lab activities using lasers
- Training staff using lasers
- Periodic review and evaluation of control measures
- Investigating any laser safety incidents
- Ensuring the lab is compliant with all laser standards and regulations
Laser safety training
It is vital that all staff using lasers are trained in:
- Their safe operation and use
- The PPE required when using the lasers
- How to safely shut down and discharge the equipment
- How to determine the beam path and contain reflections and scattered light
- How to keep other staff safe from accidental interaction with the laser beams
Lasers are powerful tools that are integral to many lab activities, including analytical methods, characterization methods, and machining activities. While these tools contribute significantly to the lab’s capacity to make scientific discoveries, the intense light beams also create hazards that can burn or seriously injure staff. Mitigating these risks is vital to using these tools appropriately and generating a safe and productive laboratory.
Embark on a transformative journey in lab safety management with the Lab Safety Management Certificate program from Lab Manager Academy. We understand the challenges you face in building your lab’s safety culture, and we're here to support you every step of the way. Our program empowers you to overcome resistance to change, nurture staff engagement, and kindle innovation within your lab, all while fostering a culture of safety. Your lab's safer future starts right here, and we're excited to be part of your journey. Discover more about the Lab Safety Management Certificate program here.
