Non-Beam Hazards
Non-beam hazards (NBH) are all hazards arising from the presence of a laser system, excluding direct exposure of the eyes or skin to a laser beam. In some cases, non-beam hazards can be life threatening.
X-Rays – Some of the high voltage systems with potentials greater than 30 kV may generate X-rays at significant dose rates. Plasma systems and ion sources operated at high voltages should also be checked for X-rays. High power (kilojoule) electron pumped Excimer lasers can generate significant X-ray levels (300 mrad per pulse at 15 feet). These devices must be checked by the Radiation Safety Office upon installation to ensure adequate shielding is included.
Plasma Radiation – Materials can be made incandescent when exposed to laser radiations. These incandescent spots are very bright and can cause serious photochemical injuries to the eyes. The laser protective eyewear may not protect against such exposures. Whenever possible, view such spots through suitable filters such as TV cameras, etc.
Fire Hazards – Class 4 visible and infrared beams with irradiances above 10 W/cm2 can ignite combustible beam enclosure materials. Keep flammables materials out of the beam line and maintain segregation between reactive reagents in the lab. Never use cardboard or paper for high power visible or infrared containment. For combustible and electrical fires, a fire extinguisher of the proper class (i.e. ABC or general purpose) must be readily accessible. Contact Auburn University Risk Management and Safety for assistance.
Laser Generated Air Contaminants (LGAC) – Air contaminates, produced by the interaction of the laser beam with the target material, can result in the production of hazardous materials. During surgical procedures, biohazardous aerosols containing blood-borne pathogens are created. The Occupational Safety and Health Association (OSHA) provides detailed information on biohazardous air contaminants produced during surgery. Fumes produced when laser radiation vaporizes or burns a target material whether metallic, organic or biological may be hazardous. Adequate local exhaust ventilation needs to be provided in the laser target zone. Contact LSO for assistance.
Chemical Hazards – Many gases and all laser dyes and solvents used in some laser systems are highly toxic. Several laser dyes are carcinogenic. When dimethyl sulfoxide (DMSO) is the solvent, the dyes may be particularly hazardous if spilled on the skin because DMSO promotes absorption through the skin. If toxic chemicals are used in a laser system, Material Safety Datasheets (MSDS) must be reviewed prior to using them. MSDSs can be accessed through manufacturers’ website. If the MSDS cannot be located, contact Auburn University Lab Safety. Potential exposures to dyes and solvents are most likely to occur during solution preparation. During solution preparation, dye and solvent mixing should be done inside a chemical fume hood. Dye pumps and tubing/pipe connections should be designed to minimize leakage. Pumps and reservoirs should be set inside spill pans. Tubing/pipe systems should be pressure-tested prior to using dye solutions and periodically thereafter. Dye solutions can be corrosive. Stainless steel heat exchangers are recommended. Keep dye handling areas clean and segregated from other operations. Gas cylinders, dyes and solvents must be properly disposed of through Auburn University Chemical Waste Collection Program. Contact Environmental Health and Safety for assistance.
Hazardous Gases and Cryogenic Materials – Flammable gases, e.g., hydrogen, and oxygen tanks present significant hazards if proper handling, manifolding, and storage precautions are not followed. Other hazardous gases may also require special handling and ventilation. Gas cylinders must be properly anchored with metal linked chains, fastened at the top and near the base of the tank to prevent falling. Such tanks can become high velocity projectiles and can cause significant property damage and injuries, contact Auburn University Lab Safety for assistance. A number of laser systems utilize toxic gases (e.g., HF). These gases must be contained in approved ventilation and manifold systems. Contact LSO for information on approved systems.
Wear appropriate protective clothing and face shields when handling large quantities of liquid nitrogen (LN) or other cryogenic materials. The normal moisture and oils present on the skin will protect against a few drops of LN spilled on the skin, but large quantities can cause severe frostbite. LN and inert gases can displace air in a room or confined area and cause asphyxiation. Good ventilation is required in areas where these gases and cryogenic liquids are used. Open dewars of liquid nitrogen can condense oxygen from the room air and cause fire or explosion hazards if the oxygen contacts a fuel.
Electrical Hazards – Most laser systems involve high potential, high current power supplies. The most serious accidents with lasers have been electrocutions. There have been several electrocution fatalities related to lasers, nationwide. Only qualified personnel may perform all internal maintenance to the laser and more than one user must be present when performing said maintenance. Make sure that high voltage systems are off and locked out, and especially that high-energy capacitors are fully discharged prior to working on a system. Beware that capacitors may have their charges restored after initial discharge. Systems should be shorted during repair or maintenance procedures. The discharge of large capacitors requires proper equipment and procedures because significant levels of stored energy can be released as heat or mechanical energy. Class 3B and/or Class 4 lasers should have a separate circuit and local cut-off switch (breaker) for the circuit. Label and post electrical high voltage hazards and switches. Clearly identify the main switches to cut-off power. Before working on a laser, de-energize the machine. Keep cooling water connections away from main power and high voltage outlets and contacts. Use double hose clamps on cooling water hoses. Inspect cooling water hoses and connections and power cables and connectors periodically as part of a regular equipment inspection. Contact Auburn University Electrical Shop for assistance in electrical service within buildings.
UV Lasers – Since UV radiation scatters easily from many surfaces, and exposure to UV radiation can cause cancer and it is important to contain UV radiation as much as possible. Wear gloves, (when hands are near the beam) long sleeve lab coats, and face and eye protection against UV radiation exposure. Avoid putting hands into the invisible beam (use fluorescent screens to define the beam). When intense UV radiation is absorbed in air, ozone will be produced and proper ventilation may be needed. Contact LSO for assistance on ozone concerns and UV radiation hazards.
Noise – Certain lasers and associated electrical devices can generate painful and unpleasant noises at high frequency or repetitive rate that are harmful to the ears. Noise levels from certain lasers, and their work environment, may be of such intensity that noise control may be necessary.
