• Introduction
• Scope and Application
• Program Description
• Roles and Responsibilities
• For More Information

Introduction

Ultra-violet light (UV) is defined as electromagnetic radiation in the spectral region between 180 and 400 nanometers (nm). Immediate or prolonged exposure to UV light can result in painful eye injury, skin burn, premature skin aging, or skin cancer. Individuals who work with or in areas where UV sources are used are at risk for UV exposure if the appropriate shielding and protective equipment are not used.

The permissible exposure limit for UV light is somewhat complicated to determine. The limit is based on the wavelengths of the specific region of the UV spectrum to which the individual is exposed, the duration of the exposure, and the intensity of the light. For this reason, the exposure limit, usually expressed in terms of exposure time, is best determined by consulting the Office of Environmental Health and Safety (EHS). As a benchmark, the threshold at which eye injury is experienced is 10 milliJoules/cm2. This level represents only seconds to minutes of exposure time for many of the UV sources used at Princeton University.

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Scope and Application

UV sources can be used or generated at a variety of locations. The areas or sources for which there is a potential for exposure to UV light include, but are not limited to:

• welding operations
• biological laboratories where gels are visualized
• areas in which germicidal UV lights are used, including biological safety cabinets
• libraries where UV light may be used to examine documents
• science laboratories where Mineralights are used to cause fluorescence
• mercury vapor lamps with broken or missing envelopes

For some of the sources described, the user many not be fully protected from UV light exposure by any inherent shielding around the source or the user may not be aware of the hazards of UV light. The purpose of the UV Light Safety Program is to ensure that the safeguards necessary to limit exposure have been implemented.

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Program Description

Monitoring

Most UV light sources have the potential of causing photokeratitis (eye injury) with only short exposure periods and should, therefore, be used in a manner which limits exposure time. EHS does not routinely measure the intensity of UV sources or determine the duration of an individual’s permitted use time. EHS will survey a source for light intensity upon request or if an accidental exposure is suspected and it is necessary to determine the potential extent of injury. Sources may also be surveyed at the discretion of EHS. Many overexposures to UV light have occurred when the exposed individual was not aware of the hazards of the UV source. To prevent eye and skin injuries, sources of UV light must be conspicuously labeled with a warning attached to the housing of the source. The warning sign should state:

or

Warning signs are available from commercial suppliers or may be available from the manufacturer of the ultraviolet light product.

UV Light Protection

The key to effectively reducing UV exposure is to properly shield the source and to require that users wear the appropriate personal protection. Personal protection that is appropriate includes welder’s masks, goggles and face shields. EHS can provide information on the appropriate protection for the source in use.

In the case of welding operations, the protection needed may also include area-enclosing curtains for the protection of bystanders. In addition, burn protection for the operator is important. Therefore, protection would include gloves, full sleeved shirts and, possibly, a fire resistant apron .

First Aid

The symptoms of UV overexposure to the skin are well known and characteristically called sunburn. However, the symptoms of overexposure to the eyes are not widely known. They are:

• a burning and painful sensation in the eye
• a sensitivity to light
• the sensation of a foreign object in the eye, sometimes described as sand in the eye
• tearing

These symptoms usually develop several hours after the overexposure occurred.

If an eye or skin injury is suspected, the individual should be examined by a physician. During work hours, employees may go to Employee Health at the McCosh Health Center. After hours, employees should go to an emergency room or their personal physician. Students should go to a physician at the
University Health Service in McCosh Health Center. Employees must visit Employee Health on the first day of returning to work.

Training

Individuals who use UV sources need training that is commensurate with the associated hazards. Training is provided by EHS and includes:

• effects of UV light
• units of measuring UV light
• recommended UV exposure limits
• types of protective equipment and shielding
• handling medical emergencies
  

It is the responsibility of the supervisor to assure that individuals using UV light sources attend training and to keep records of attendance.

Access to Information and Recordkeeping

EHS will maintain a list of personnel who have attended UV Safety Training. Copies of the list are provided to the department and supervisor. Results of surveys, recommendations for corrective actions and exposure investigations are provided by EHS to the department and supervisor for their information and to initiate any necessary corrective measures.

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Roles and Responsibilities

Department

• Notify EHS when new UV sources are obtained.
• Minimize UV exposure by providing goggles, face shields or masks, as appropriate, and other protective devices and equipment.

Supervisor

• Post signs and/or stickers near or on UV sources.
• Ensure workers receive training.
• Ensure workers wear UV personal protection.
  

EHS

• Provide training when requested by the department, supervisor or individual.
• Conduct monitoring upon request.
• Investigate overexposures and provide recommendations to prevent reoccurrence.
• Audit department program periodically.
  

Individual

• Attend training.
• Wear appropriate UV protection described above.
• Observe exposure duration limits.
• Report overexposures to the supervisor and EHS.

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Contact EHS Health Physics at 258-5294.

An Ultra-Violet Light Safety Self-Audit Checklist is available through EHS or may be downloaded either as a PDF or a customizable Word document.

The following reference is available through EHS:

• Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices, American Conference of Industrial Hygienists, published annually.
• Links to other ultraviolet light and safety related web sites are available here.

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