All CFLs contain mercury, typically about 4 mg. Some manufacturers have reduced the amount to as little as 1 mg in some types of CFLs, and more manufacturers are following suit. Today, very few household products contain any mercury. Before the 1980s you could find mercury in paint, pesticides, dental fillings and fever thermometers.
Is 4 mg a “small” amount?
Relatively speaking, yes. Four mg of mercury easily fits on the tip of a ballpoint pen. A glass thermometer contains 100 to 600 times as much mercury as today’s typical CFL. (While glass thermometers are no longer used, it’s a useful comparison).
Despite the small amount in a CFL, that doesn’t discount the fact that mercury is harmful. So, does the amount of mercury getting into the environment through increased CFL use offset the amount of mercury and other pollutants that get into the environment through coal-fired generation?
According to the Environmental Protection Agency (EPA), the milligrams of mercury emitted annually by the burning of coal to create electricity for:
A 26-watt CFL equals 0.66 mg
A 100-watt incandescent bulb equals 2.52 mg
But what if you live in a state that generates large amounts of its electricity through renewable energy? More than 40% of South Dakota’s energy is alternative. Still, that’s 75% less mercury for any coal-generation remaining.
Bottom line: The use of CFLs emits far fewer mercury emissions than the use of incandescent bulbs – even when accounting for the rise of renewable-energy generated electricity.
When the End is Not the End
We must recycle our spent CFLs. If not a single CFL is recycled, the mercury savings are negated, according to a somewhat old but math-tastic article from Energyrace.
Recycling spent CFLs is highly recommended and, in many states, it’s the law. Thankfully, recycling stations are becoming more available. And since many recycling stations are located in or near stores you likely already frequent, you shouldn’t need to drive farther (thus, use more gasoline) to recycle.
Article by Mary LaLone, appearing courtesy Xcel Energy Blog.