Laser Safety Manual

34 Laser Safety Manual Fire Hazards Class 4 lasers represent potential fire hazards. Depending on the construction material, beam enclosures, barriers, stops, and wiring are potentially flammable if exposed to high beam irradiance for more than a few seconds. Under some situations where flammable compounds or substances exist, it is possible that fires can be initiated by Class 3 lasers. Laser-Generated Air Contaminates (LGAC) Air contaminates may be generated when certain Class 3B and Class 4 laser beams interact withmatter. The quantity, composition, and chemical complexity of the LGAC depend greatly upon target material, cover gas, and the beam irradiance. Some compounds may be gaseous or particulate and can, under certain conditions, pose occupational concern. For further information, contact your safety office. Plasma Emissions Interactions between very high-power laser beams and target materials produce plasmas that may contain hazardous UV emissions. Plasma emissions created during laser-material interactions may contain sufficient UV and blue light (0.18 to 0.55 um) to raise concern about long-term ocular viewing without protection. UV and Visible Radiation Laser discharge tubes and pump lamps may generate UV and visible radiation. The levels produced may exceed the MPE limit and cause skin and eye damage. Photosensitizing agents from industrial chemicals or medications can make an individual more susceptible to these effects.