Division of Environmental Safety and Health
Radiation Protection and Release Prevention Element
Bureau of Environmental Radiation
Nonionizing Radiation Section
PO Box 415
Trenton, New Jersey 08625-0415

Phone: (609) 984-5521
Fax: (609) 633-2210

TO: School Superintendents

RE: Mercury Vapor Lamps

Date: May 19, 2004

It has come to our attention that some schools are using the wrong type of mercury vapor lamps in gymnasiums, to illuminate sports fields, or anywhere bright light is needed. The improper use of these lamps or bulbs may result in serious eye and/or skin injury. The purpose of this letter is to inform you of the Department of Environmental Protection’s (Department) regulations governing the use of mercury vapor lamps and their potential health hazards.

Mercury vapor lamps are composed of an inner quartz tube containing the mercury vapor, enclosed by an outer envelope that filters out harmful short wavelength ultraviolet (UV) radiation. If the outer envelope is broken and the lamp continues to operate, intense UV radiation is emitted. The lamp may even appear to look like it is off but continue to transmit UV. The UV radiation from these lamps is more hazardous than sunlight because the length of the wave is shorter and therefore, carries more energy. Even minutes of exposure to this type of radiation may result in skin reddening and the destruction of the outermost cells of the cornea and/or the conjunctiva. Symptoms include a sensation of sand in the eye that may not be felt until six to eight hours after the exposure. The eye may tear and vision may be blurred for as long as two days. The extent of skin and eye damage depends on a number of things, such as: lamp wattage, exposure time, distance of the lamp from the exposed persons and individual sensitivity. The Food and Drug Administration (FDA) recommends that people near a broken mercury vapor lamp 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.

Most injuries have occurred in school gymnasiums after the lamps were struck and partially broken by sports equipment. In the case of an outdoor installation, damage may be due to vandalism. Also, since mercury vapor lamps operate at high pressure and high temperatures, they may explode without any outside influence.

There are 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 shortwave UV, or in areas where people will not be exposed to UV radiation if the outer globe is broken. The Department strongly recommends that you check your facilities now for compliance with the requirements set forth in N.J.A.C. 7:28-41, Mercury Vapor Lamps so that if there is a problem, your facilities can be brought into compliance before the beginning of the 2004-2005 school year in September. You may reference the regulation at the following website: http://www.nj.gov/dep/rpp/nrs/nrsregs.htm.

As you are now aware, mercury vapor lamps may pose a health risk if not properly maintained. The FDA has generated a checklist that should be followed to avoid injury from their usage:

  1. Examine the lamps regularly for missing, broken or punctured outer bulbs. This should be done with the lamps off.
  2. If a lamp is broken, turn the lamp off immediately.
  3. Replace lamps only when the lamps are off.

Persons exposed to UV from a damaged lamp should see a doctor if symptoms of skin burns or eye irritation occur. Your local health department should also be contacted, as there may be ancillary health issues such as exposure to mercury vapor if a lamp in an indoor or confined space is shattered or the inner quartz envelope cracked. In addition, it is requested that all injuries or incidences involving broken lamps be reported to the Nonionizing Radiation Section as soon as possible. You may either call 609-984-5521 or e-mail Ms. Deborah Riggs Wenke at debbie.wenke@dep.state.nj.us. Ms. Wenke will also be happy to answer any questions you may have regarding the contents of this memorandum.

For additional information on mercury vapor lamps, please visit the Department’s website at http://www.nj.gov/dep/rpp/nrs/mercvapr.htm. Thank you for your anticipated cooperation in this matter.

c: County Superintendents


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Department of Environmental Protection
P. O. Box 402
Trenton, NJ 08625-0402