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Mercury She Wrote

By John Mauer

As the cost of electricity rises, most of us want to save money.  This leads many of us to replace our incandescent bulbs with compact fluorescent lamps (CFL) which are known to use less power.  However, most CFLs contain a small amount of Mercury, which is toxic especially if the bulbs are broken while hot.  Now, a new report by the German Federal Environmental Agency shows that such Mercury emissions in the home can be dangerous, especially to young children and pregnant women.


Fluorescent bulbs are ever present in most businesses, schools, and municipal buildings although they are usually recessed to prevent breakage.  They work by passing an electrical current through Mercury vapor.  The vapor is excited and emits high energy invisible ultraviolet light.  This ultraviolet light, in turn, hits phosphors on the inside of the glass surface.  The phosphors absorb the ultraviolet light and reemit it as visible light.

Because less of the energy in fluorescent bulbs is lost to heat, they are more efficient than normal incandescent bulbs.  Incandescent bulbs get light by heating a Tungsten filament until it glows.  That energy savings is typically 67-80%.  The average American household uses about 9% of its electricity in lighting.  Replacing all your incandescent light bulbs with CFLs could mean as much as a 7% savings.  Of course, for those of us in the north, most of that savings is lost in the winter to the need for extra heat; those incandescent bulbs are great space heaters.

However, fluorescent lamps do contain Mercury, which is toxic, especially when heated.  A report by the German Federal Environmental Agency (UBA) outlines tests and recommends what to do if a bulb breaks, as might happen if a lamp is pushed over.   The agency broke two lit bulbs, with 2mg and 5mg of Mercury, and measured the Mercury vapor.  The resulting vapor was 20 times higher than their guidelines for safety.  They recommended that such bulbs should have protective casings, and be avoided in children’s rooms.

“The presence of mercury is the downside to energy saving lamps. We need a lamp technology that can prevent mercury pollution soon,” said UBA President Jochen Flasbarth. “The positive and necessary energy savings of up to 80 percent as compared to light bulbs must go hand in hand with a safe product that poses no risks to health.”

Handling a broken fluorescent bulb also presents risks.  Using a vacuum cleaner is the worst possible remedy.  The residual Mercury vapor in the phosphors is immediately vaporized increasing toxic exposure.  (For those of us who remember Mercury thermometers, the problem here is the added heat of the vacuum motor.)

According to the U.S. Environmental Agency, the proper way to clean up and dispose of a broken bulb is:

  • Have people and pets leave the room, and don’t let anyone walk through the breakage area on their way out.
  • Open a window and leave the room for 15 minutes or more.
  • Shut off the central forced-air heating/air conditioning system, if you have one.
  • Carefully scoop up glass pieces and powder using stiff paper or cardboard and place them in a glass jar with metal lid (such as a canning jar) or in a sealed plastic bag.
  • Use sticky tape, such as duct tape, to pick up any remaining small glass fragments and powder.
  • Wipe the area clean with damp paper towels or disposable wet wipes. Place towels in the glass jar or plastic bag.
  • Do not use a vacuum or broom to clean up the broken bulb on hard surfaces.
  • If any clothing, bedding, or other soft materials come in direct contact with the broken bulb, discard them as above.  Immediately wash any such materials that may have been exposed to the vapor.

The Connecticut Department of Environmental Protection recommends all Mercury containing items to be recycled at household hazardous waste collections.  All businesses, schools, and municipal users must dispose of them as toxic waste.

As an alternative, Halogen lamps offer some energy savings, and LED lamps are just around the corner.



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