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    Make It A Safe Day With Lasers
    By Hatice Cullingford | July 22nd 2009 03:59 PM | Print | E-mail | Track Comments
    About Hatice

    Welcome to my universe.. where there is Peace University. As Fine Scientist, PhD, I write about my interest in various fields, from energy to space...

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    Health requires safety. There is a laser hazard that the Food and Drug Administration (FDA) is concerned about: the increased availability in stores and on the Internet of certain types of laser products.  A laser can be unsafe when misused as a toy or directed at people, vehicles, or aircraft. 

    The laser acronym stands for light amplification by stimulated emission of radiation.  FDA regulates radiation-emitting electronic products, including all types of lasers. Manufacturers of some types of laser products that are powered above 5 mW must obtain permission from FDA before they are sold to the public. This power limit applies to lasers sold to the public for purposes of alignment, surveying, or leveling, and includes lasers used for pointing. Laser projectors powered above 5 mW and the laser light shows that they produce must also be manufactured with permission from FDA.

    Warning symbol for laser beam


    There are many different types of lasers depending on type of laser medium in use. Laser  media commonly include gases such as argon, carbon dioxide, nitrogen or a helium and neon mixture, solid crystals such as ruby, and liquid dyes or chemicals. When energy is applied to the laser medium, it becomes excited and releases energy as particles of light (photons). A pair of mirrors at either end of the sealed tube either reflects or transmits the light (see FDA figure below) in the form of a concentrated stream called a laser beam. Each laser medium produces a beam of a unique wavelength and color

    Graphic of a laser which shows the sealed tube with laser medium, mirror that both reflects and transmits, the laser beam and a mirror that totally reflects


    Lasers are employed for a variety of purposes including pointing out objects during a presentation, aligning materials at construction sites and in the home, and by doctors for cosmetic and surgical procedures. Some of the laser applications in daily life are CD and DVD players; fiber-optic communication, bar code scanners; dental drills; laser-guided tools, such as levels; and laser printers.

    Two characteristics of laser light contribute to the hazard:
    • Laser light can be emitted in a tight beam that does not grow in size at a distance from the laser. This means that the same degree of hazard can be present both close to and far from the laser.
    • The eye can focus a laser beam to a very small, intense spot on its retina, which can result in a burn or blind spot.
       

    The FDA requires labels on most laser products that contain a warning about the laser radiation and other hazards, and a statement certifying that the laser complies with FDA safety regulations. The label must also state the power output and the hazard class of the product. The FDA recognizes four major hazard classes (I to IV), including two subclasses (IIIa and IIIb), of lasers--ranging from those that pose no known hazard to those that pose serious danger if used improperly. The higher the class is, the more powerful the laser is. Consumer laser products are generally in classes I, II, and IIIa, while lasers for professional use may be in classes IIIb and IV.

     FDA Tips for Consumers

    • Never aim or shine a laser at anyone, including animals.
    • Look for the following information on the label to make certain that a laser (or a toy that includes a laser) is safe:
    · a statement that it complies with Chapter 21 CFR of the Code of Federal Regulations
    · the manufacturer’s or distributor’s name and the date of manufacture
    · a warning to avoid exposure to laser radiation
    · a class designation up to Class IIIa.
    • Be aware that the manufacturer of a Class IIIb or IV laser product must obtain permission (also called a "variance") from FDA before the laser is sold to the public if the laser product:
    · is designed, intended, or promoted for surveying, leveling, or alignment (which includes pointing)
    · is a demonstration laser product (which includes laser projectors) that is designed, intended, or promoted for purposes of demonstration, entertainment, advertising display, or artistic composition.

    Surveying, leveling, or alignment laser products and demonstration laser products mentioned directly above that are powered above 5 mW with no label that indicates they were manufactured under a variance present a serious safety hazard and are not legal for sale.
     
     
    Sources: fda.gov, wikipedia.org,nobelprize.org