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ABC of Safety in the Biological Sciences
Laser Hazards
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Eye -- Damage can occur from both acute and chronic exposure to laser radiation depending on the wavelength and exposure levels. Corneal and/or retinal burns can result from acute overexposure. Cataracts and/or retinal injury may be caused from chronic exposure to excessive levels of radiation.
Damage to the retina can result from visible and near-infrared radiation, (400 to 1400 nm). Light directly from the laser or reflection from a mirror-like surface entering the eye, can be focused to an extremely small image on the retina due to the focusing effects of the cornea and lens.
Laser radiation in the middle-ultraviolet, (200 to 315 nm), and far-infrared, (3 micrometer to 1 mm), produce damage principally at the cornea.
Radiation in the near-ultraviolet, (320-390 nm), and middle-infrared, (1.4 -3 micrometer, passes through the cornea with little damage but effects the lens behind the cornea.
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Skin -- Burns can result from acute exposures to high levels of optical radiation. Some specific ultraviolet wavelengths can cause carcinogenesis of the skin.
Erythema, (sunburn), skin cancer and acceleration skin aging are possible from exposure of laser radiation in the range of 0.2 to 0.28 micrometer. Chronic exposure of 0.28 to 0.4 micrometer wavelength radiation can cause increased pigmentation. Photosensitive reactions are possible from wavelengths in the range 0.31 to 4 micrometer while skin burns and excessive dry skin effects are possible from radiation in the range of 0.7 to 1 micrometer.
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Chemical Hazards -- Reactions induced by laser use can release hazardous particulate and gaseous products. Example of this are in material processing such as laser welding, cutting, and drilling all of which can create potentially hazardous fumes and vapors. General ventilation safety procedures should be used when lasers are used in this manner.
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Electrical Hazards -- The danger is from the high-voltage power supply needed to fire up a laser. Always practice commonly accepted electrical safety procedures.
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Other Secondary Hazards -- High-power lasers and lasers with continuous-wave output with power well above one-half watt have the potential to cause fire hazards. Another hazard associated with these types of lasers is working with cryogenic coolants such as liquid nitrogen. Skin contact can cause burns, improper plumbing can cause explosion, and insufficient ventilation can result in displacement of oxygen by the liquified gas vaporizing.
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