page_title: Laser safety
section_title: Old system
hierarchical_section_title: Laser safety / Classification / Old system
context_page_description: Laser safety is the safe design, use and implementation of lasers to minimize the risk of laser accidents, especially those involving eye injuries. Since even relatively small amounts of laser light can lead to permanent eye injuries, the sale and usage of lasers is typically subject to government regulations.
  Moderate and high-power lasers are potentially hazardous because they can burn the retina, or even the skin. To control the risk of injury, various specifications, for example 21 Code of Federal Regulations Part 1040 in the US and IEC 60825 internationally, define "classes" of laser depending on their power and wavelength. These regulations impose upon manufacturers required safety measures, such as labeling lasers with specific warnings, and wearing laser safety goggles when operating lasers. Consensus standards, such as American National Standards Institute Z136, provide users with control measures for laser hazards, as well as various tables helpful in calculating maximum permissible exposure limits and accessible exposures limits.
context_section_description: The safety classes in the "old system" of classification were established in the United States through consensus standards (ANSI Z136.1) and federal and state regulations. The international classification described in consensus standards such as IEC 825 (later IEC 60825) was based on the same concepts but presented with designations slightly different from the US classification.
  This classification system is only slightly altered from the original system developed in the early 1970s. It is still used by US laser product safety regulations.  The laser powers mentioned are typical values. Classification is also dependent on the wavelength and on whether the laser is pulsed or continuous. For laser classes 1 to 4, see the section on the revised system above.
caption: Green laser – class IIIb compared to class IIIa
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