Laser and Optical Radiation

 Ultraviolet (UV) and High Intensity Optical Sources (HIOS)

Last Updated: August 13, 2018
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HIOS and UV radiation sources are commonly overlooked when considering hazardous optical radiation sources.  UV radiation is present in sunlight, and is emitted by UV-A "black light" lamps, UV LEDs, mercury vapor lamps, tanning lamps, and other types of lamps.

UV sources and HIOS present unique nonionizing radiations hazards when compared to hazards from lasers.  With UV and HIOS, there are chronic effects such as cataract formation from long-term IR exposure, skin cancer from UV exposure, and possible photochemical retinal injuries due to visible blue-light exposures.  Low-level effects such as discomfort, glare, or temporary flashblindness also exist.  These sources are known as "broadband" sources due to emitting more than one wavelength of light.  Broadband sources can be difficult to analyze due to multiple wavelengths, capturing short duration emissions (such as in an explosive device), multiple damage mechanisms to evaluate, and varying safety limits that change depending on source size and exposure duration.  A few areas of concern are:

Explosive Devices:

Diversionary (flashbangs) and training devices (training grenades) can cause injuries at close range when improperly used. 
The exposures from these are commonly a very short, bright flash that can potentially be hazardous for momentary viewing.  Thermite, flares, incendiary detonantions are the brightest chemical reactions measured to date and are often designed to sustain the reaction for prolonged durations. These types of emissions are not usually a momentary viewing hazard, but can be hazardous if one were to stare at reaction.

Welding:

Welding and cutting arc processes present a wide range of hazards in addition to optical radiation.  These include but are not limited to fire, fragments and sparks, fumes, noise, volatile gases, and electrical hazards.  Be aware that reflections carry the same hazards as direct viewing and to protect yourself and others from refelctions by wearing safety glasses with UV protective side shields.  Use curtains and other shielding devices to avoid exposing passerby.  Be sure to wear adequate gloves and clothing to protect exposed skin.   
Some useful regulations and authoritative documents:
•Federal regulations – 29 CFR 1910, Subpart Q
•ANSI Z49.1 and Z87.1

Searchlights and Arc Lamps:

Searchlight users who are unaware of the danger may treat these devices as casually as they would a flashlight. Proper awareness and training are necessary to prevent injuries from the use of these devices. These searchlights pose a hazard to the eye and to a lesser extent the skin. The visible and NIR radiation may be so intense that retinal burns can occur at close distances even with a moment’s exposure. Repeated exposures can increase the hazard, but these are unlikely because of the brightness of the beam. Searchlights may also include NIR filters for night vision use. A retinal hazard at close range may still be present, even though searchlights with NIR filters will visibly appear much less bright. This can lull bystanders into a false sense of safety. The searchlight beam can also burn the skin at close distances, but the heat from the beam usually provides sufficient warning. Minor effects like glare discomfort are also possible, and these symptoms can occur with exposures that are well within the safety limits. See Hazard Alert for Handheld and Weapon-Mounted Searchlights for more information

UV and Medical Lamps:

Many medical and UV lamps do not appear visibly bright. Exposed persons may not be aware of hazard, or may underestimate the hazard.  Some types of medical/UV lamps are: operating microscopes have been known to be the cause of some retina and soft tissue injuries. Doctors trained to minimize exposures will reduce the risk of injuries as well as the use of filters to reduce UV, IR risks.  Phototherapy lamps used in dermatology therapy and – should have controlled exposures, timers, protective eyewear and clothing as needed; those used in Neonatal, bilirubin therapy should have filters, protective eyewear
•Curing lamps – filters, protective eyewear, minimize exposures
•Fluorescence inspection lamps
–Not just medical (security, industrial)
–Admin controls should be enough


Common Locations of HIOS

  • Air Handler Units (May include internal germicidal lamps for mold control that should be interlocked)
  • Maintenance Areas/Depots (Welding)
  • Units (Welding, Searchlights)
  • Hospital/Health Clinic/Dental Clinic (Pulsed xenon or low pressure mercury disinfection lamps):
    • Newborn/Neonatal Clinic (hyperbilirubinemia (bili) lights)
    • Dermatology (phototherapy booths, hand/foot units)
    • Veterinary Clinics
    • ER
    • Ophthalmolgy (UV illumination lamps ('Woods' lamps))
    • Pathology
    • Immunology
    • Molecular Biology (Flow Cytometers)
    • Pathology (Cryostats with germicidal lamps (should be interlocked)
    • Histology
    • Microbiology
    • Pharmacy (Germicidal lamps in laminar flow hoods)
    • Dental Clinic (UV curing lamps)
    • Medical Maintenance (welding)
    • Surgical Centers (Upper room low pressure mercury lamps,
  • Research Labs (Xenon arc lamps)
  • Biomedical Research (Germicidal lamps in laminar flow hoods, UV gel transilluminator)
  • Industrial Facilities (Welding, Foundry Furnaces, Electric Arc Metallizers, Thermal Heat Treaters, Forge Shops)
  • Welding Shops (DPW, Logistics, automotive self-service, individual military units)
  • Gymnasiums (Metal halide and mercury vapor lights used for general lighting (These don't normally pose a hazard unless their outer envelope breaks and the lamp isn't a self-extinguishing type. However, the people that work there might not be aware of that risk.)
  • Security/Military Police/Criminal Investigation (Fluorescence inspection lamps - Wood's lamps)