Hazards of high-intensity discharge lights

Metal halide lights and other high-intensity discharge lights – frequently used in indoor and outdoor facilities – can lead to eye injuries, according to the Washington State Department of Labor and Industries.

High-intensity discharge lights are available in three basic types: metal halide, mercury vapor and high-pressure sodium lights. Metal halide and mercury vapor lights are used in warehouses, warehouse-type retail stores and sports facilities. High-pressure sodium lights often are used for street and highway lighting. When these lights are turned on, they can produce potentially harmful levels of ultraviolet radiation. Washington L&I stresses that this is not a concern as long as the light is undamaged. However, cracked bulbs or covers can expose workers to harmful UV radiation, often without an individual even being aware.

Possible health effects range from skin irritation and temporary loss of vision to severe skin burns and long-term damage to the eye’s cornea, depending on the length of exposure. Washington L&I warns that the onset of symptoms and health effects from overexposure to UV radiation is often delayed.

To protect against high-intensity discharge light hazards, the department recommends workers:

• Know where these light sources are located in their work area and how the lights can become hazardous.
• Be familiar with how to report observations of broken glass and cracked bulbs and covers, as well as incidents in which lights may have been struck with equipment or other objects.
• Be aware that the lights may still work even when damaged.
• Know how to take proper safety precautions when inspecting or replacing lights. For example, properly disconnect the power when removing bulbs, and always check exposed electrical contacts with an appropriate sensor before making contact.