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Ultraviolet Radiation Hazards

Description

Common Sources of UV Radiation in the Laboratory

Hazards Associated with Exposure to UV Radiation

Special Work Practices

Equipment Labeling

Personal Protective Equipment

Emergency Procedures

EH&S Services

Description

Ultraviolet light (UV) is a non-ionizing radiation found in the 180 to 400 nanometer wavelength region of the electromagnetic spectrum.  The UV spectrum is commonly divided into the following three regions:

Region

Name

Wavelength (nm)

UV-A

Black Light

315-400

UV-B

Erythemal

280-314

UV-C

Germicidal

180-280

Exposure to UV radiation is typically limited to the UV-A region resulting from exposure to direct sunlight.  The Earth’s atmosphere shields us from the more harmful UV-C and greater than 99% of UV-B radiation.  However, some equipment can generate concentrated UV radiation in all the spectral regions that, if used without the appropriate shielding and personal protective equipment, can cause injury with only a few seconds of exposure.

 

Common Sources of UV Radiation in the Laboratory

There are several sources of UV radiation in the laboratory including germicidal lamps in biological safety cabinets, nucleic acid transillumination boxes, nucleic acid crosslinkers, and UV lasers. 

For laser safety information, please refer to the NCSU Laser Safety Manual

 

Hazards Associated with Exposure to UV Radiation

An unfortunate property of UV radiation is that there are no immediate warning symptoms to indicate overexposure.  Symptoms of overexposure including varying degrees of erythema (sunburn) or photokeratitis (welder’s flash) typically appear hours after exposure has occurred.

Skin Injury - UV radiation can initiate a photochemical reaction called erythema within exposed skin.  This “sunburn” can be quite severe and can occur as a result of only a few seconds exposure. Effects are exaggerated for skin photosensitized by agents such as coal tar products, certain foods (e.g., celery root), certain medications and photoallergens.  Chronic skin exposure to UV radiation has been linked to premature skin aging, wrinkles and skin cancer.

Eye Injury – UV radiation exposure can injure the cornea, the outer protective coating of the eye.  Photokeratitis is a painful inflammation of the eye caused by UV radiation-induced lesions on the cornea. Symptoms include a sensation of sand in the eye that may last up to two days. Chronic exposures to acute high-energy UV radiation can lead to the formation of cataracts.

 

Special Work Practices

Never allow the skin or eyes to be exposed to UV radiation sources.  The UV radiation generated by laboratory equipment can exceed recommended exposure limits and cause injury with exposures as brief as three seconds in duration.

  • Biological Safety Cabinets – Never work in a biological safety cabinet while the germicidal lamp is on.  If possible, close the sash while lamp is on.
  • Transilluminators – Never use a transilluminator without the protective shield in place.  Shields must be kept clean and replaced when damaged.
  • Crosslinkers – Crosslinkers must not be used if the door safety interlock is not working properly.

 

Equipment Labeling

Many overexposures to UV radiation have occurred as a result of individuals not knowing the hazards associated with UV-emitting equipment.  To help prevent eye and skin injuries, any equipment that emits UV radiation must be conspicuously labeled with a caution label.  The label should contain language similar to:

CAUTION
UV RADIATION HAZARD
USE ONLY WITH SHIELDING IN PLACE
PROTECT EYES AND SKIN FROM
EXPOSURE TO UV LIGHT

Caution labels should be available from the manufacturer of the UV light product.  Contact Environmental Health & Safety (EH&S) if unable to find labels.

 

Personal Protective Equipment

  • Protective Clothing – Wear standard laboratory apparel including a fully buttoned lab coat, long pants, and closed toe shoes.  While working with UV radiation sources, lab workers must be particularly careful to prevent gaps in protective clothing that commonly occur around the neck and wrist areas.
  •  Eye/Face Protection – If there is any potential for the eyes and face to be exposed to UV radiation, a polycarbonate face shield stamped with the ANSI
    Z87.1-1989 UV certification must be worn to protect the eyes and face.  Ordinary prescription eyeglasses may not block UV radiation.  UV certified goggles and safety glasses will protect the eyes, but it is not uncommon for lab workers to suffer facial burns in the areas not covered by the goggles or glasses.
  • Gloves – Wear disposable nitrile gloves to protect exposed skin on the hands.  Make certain wrists and forearms are covered between the tops of gloves and the bottom of the lab coat sleeves.

 

Emergency Procedures

If you start to experience symptoms of UV exposure, seek medical attention at once.  Notify EH&S as soon as possible.

  • Students – Report to the Student Health Center located at the corner of Cates Avenue and Dan Allen Drive.
  • Faculty & Staff – Report to Rex Urgent Care located at 3100 Blue Ridge Road.

 

EH&S Services

EH&S has equipment that can measure UV radiation generated by laboratory sources.  With accurate measurements EH&S can provide exposure assessments for lab occupants.  The degree of shielding provided by personal protective equipment can also be determined. 

EH&S is also available for training on safe work practices with UV equipment.  Contact EH&S at 515–6860 for assistance or for any questions concerning UV producing equipment.