IStock Photo 7292262 © Stephan Drescher

The life expectancy of an everyday, 60-watt incandescent light bulb is about 1,000 hours. Not far from San Francisco, a bulb in Livermore, California defies those odds. The longest burning light bulb on record, it is more than 900,000 hours old and counting. The bare bulb hangs from the ceiling of a firehouse.

The location is fitting given the long history shared by light bulbs and fires. In 1890, the first plant in the world to provide electric lighting from a central station burned to the ground. No one was hurt, but all of the machinery that once illuminated about 600 homes was destroyed. Workers on Wall Street temporarily used candles and oil lamps for light.

In 1942, a 7.5-watt electric bulb caused the largest nightclub fire in US history at Boston’s Cocoanut Grove. After a couple that wanted to turn on some romance turned off a bulb, a bartender instructed a teenage busboy to replace it. A spark ignited a nearby paper palm tree and within minutes the building was in flames. By the next morning, 492 had perished, about 1 of every 2 people who went to the Cocoanut that night seeking jazz and cocktails.

Today, few light bulbs cause death, but there are still some things to worry about.

You can cut yourself, burn yourself, electrocute yourself, or fall when trying to reach a high-up bulb. People tumble off of everything from ladders to lawnmowers.

The US Consumer Product Safety Commission estimates that light bulbs caused 13,427 injuries just in 2008. Its collection of the year’s case reports range from the predictable (“cut hand on light bulb”) to the graphic (“a piece of the glass went into elbow that got infected abscess”).

There are party traumas (“24 year old male was at go-go bar and dancer kicked light bulb and it fell on patient, believes some of it is stuck in ear”), reinforcements that beauty is pain (“burn to hand, mom at home with hot lamp on ‘doing eyebrows,’ lamp knocked over”), and scenarios that read like slapstick (“changing light bulb, stepped on dog’s back, falling backwards onto coccyx, low back pain, coccyx, neck”).

The odds a person will visit an emergency department due to an accident involving a light bulb in a year are 1 in 22,500. It’s just one of the issues that keep medical professionals busy, so it’s probably inevitable that misspellings and shorthand find their way into the reports (“touched a lite bulb with wet finger and got electric shock”).

If these seem relatively benign, stop right there. There are serious concerns about the latest bulbs on the market.

Campaigns like Ban the Bulb and Energy Star encourage the use of compact fluorescent light bulbs (CFLs) over traditional incandescent bulbs. The Department of Energy and Environmental Protection Agency claim that the energy saved by replacing one bulb in every US home with a qualified CFL bulb is enough to light more than 3 million homes for a year.

Sound too good to be true? Perhaps. Each CFL contains glass tubing enclosing about 4-5 milligrams of mercury, a toxic metal that can affect the brain, spinal cord, kidneys, and liver.

But don’t start panicking yet. Compared to the 500 milligrams present in older thermometers and 3000 milligrams present in many manual thermostats, the amount of mercury in CFLs is extremely small, about the size of a pen tip. Moreover, the reduced energy consumption of CFLs may actually reduce total net mercury emissions.

Mercury can only escape a broken bulb. Chances are such small exposure will not cause significant health risks, but the federal government advises handling them carefully and recycling them at proper locations to ensure that bulbs remain intact.

One of the greatest advantages of CFLs is their life expectancy: 6,000-15,000 hours. It remains to be seen if they can match the 108 years of Livermore’s light, but that one will probably remain in a class of its own.

In 1976, a full police and fire truck escort accompanied the light bulb to its current location. In 2001, President George W. Bush sent his congratulations for the bulb’s display of “ Yankee ingenuity.” Not bad for a little light. Given its importance, should you wish to visit the bulb, simply ring the bell at the back of Livermore’s Fire Station No. 6. A fireman will bring you inside.