Melissa Kaplan's
Herp Care Collection
Last updated January 1, 2014

More on Mercury Vapor Lamps

Compiled by Melissa Kaplan

Excerpted from Playing It Safe at Work, by Jessica Auerbach
FDA Consumer Magazine, 1991

When most people think of workplace hazards, they picture mines, factories, or a construction site. Not many would consider a school gymnasium or a comfortable office an unsafe place to work. However, even the most mundane work environments can pose health hazards that might range from mild discomfort to serious injury or illness. In some cases, the Food and Drug Administration plays a role in limiting these hazards.

Mercury Vapor Lamps
Mercury vapor lamps, most often used to light streets, gymnasiums, sports arenas, banks, and stores must be maintained properly to be safe. These lamps are composed of an inner quartz tube containing the mercury vapor, enclosed by an outer envelope that filters out harmful short wavelength ultraviolet radiation. If the outer envelope is broken and the lamp continues to operate, intense ultraviolet radiation is emitted.

UV exposure at this level has produced photokeratitis (corneal burns) and reddening of the skin, as well as blurred or double vision, headaches, nausea, and diarrhea. Most injuries have occurred in school gymnasiums after the lamps were struck and partially broken by sports equipment.

FDA issued a performance standard for high-intensity mercury vapor discharge lamps on March 7, 1980, allowing the manufacture of two types of mercury vapor lamps. One type, marked "T," is equipped with a self-extinguishing device that shuts the lamp off within 15 minutes after the outer envelope is broken. The other type of lamp, marked "R," does not contain a self-extinguishing feature. It may be used only in a fixture with a glass or plastic shield capable of absorbing hazardous ultraviolet radiation, or in areas where people will not be exposed to UV radiation if the outer globe is broken.

A 1980 FDA alert defines labeling that must appear on non-self-extinguishing mercury vapor lamps. This labeling includes the following instructions:

• Check the lamps regularly for missing, broken or punctured outer bulbs. This should be done with the lamps off.

• If a lamp is broken, turn the lamp off immediately.

• Replace lamps only when the lamps are off.

• Persons exposed to ultraviolet radiation from a damaged lamp should see a doctor if symptoms of skin burns or eye irritation occur.

• Report injuries to your state health department and to FDA.

The labeling for self-extinguishing "T" lamps must also state:

"This lamp should self-extinguish within 15 minutes after the outer envelope is broken or punctured. If such damage occurs, TURN OFF AND REMOVE LAMP to avoid possible injury from hazardous shortwave ultraviolet radiation."

People near a broken mercury vapor lamp should leave the area immediately while taking steps to limit UV exposure to their eyes and skin by donning outerwear (coats or sweaters, for example) and sunglasses.

Ocular complications of malfunctioning mercury vapor lamps.
Thun MJ, Altman R, Ellingson O, Mills LF, Talansky ML. Ann Ophthalmol 1982 Nov;14(11):1017-20

We report an outbreak of keratoconjunctivitis and skin erythema caused by ultraviolet radiation from a damaged high-intensity mercury vapor lamp. Twenty-six persons became ill after using a basketball court; symptoms included conjunctivitis (100%), skin erythema (54%), and punctate keratitis (19%). This outbreak is one of 37 similar episodes involving at least 629 persons reported to the Food and Drug Administration since 1969. Physicians should be aware that damaged high-intensity mercury vapor lamps are a continuing public health problem with substantial morbidity. Measures to prevent such occurrences are suggested.

Note that these MV lamps were significantly farther away from the players than herp keepers are from the MV lamps used to provide heat and UVR.

Excerpt from Dr. Michael Holick speaks on UV and D3...and iguanas

I asked Dr Holick about the practice of exposing reptiles to mercury vapor lamps or carbon arc lamps for a few minutes each day. He replied that these lamps have a significant output of UVC, which can result in many problems, including weakness of the immune system. What about owners? 'Owners too.'

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