Mercury in CFLs

As the mercury is soaring around the northern hemisphere these summer months, Green Blizzard wanted to address the concern and myth about high levels of mercury in compact fluorescent lights (CFL)

CFL lightbulb (2)

If you’re thinking about changing out more of your bulbs from the old fashioned incandescent to CFL, it makes, even more, sense to do so in the warmer months because incandescent bulbs only use about 10% of the consumed energy generating light and the other 90% is wasted generating heat. So why burden your AC or fans with unnecessary levels of heat.  If you are in doubt, then carefully place your hand near any of one of your incandescent clunkers, (invented more than 100 years ago!)

Why make your air conditioner work harder in the summer by having to cool down the heat generated by the energy hogs?  Why waste coal generated electricity to heat up your rooms just to spend even more energy to cool it down to a comfortable temperature.  It’s about the same as making fire in your fireplace in July.

CFL naysayers are quick to counter with the fear of mercury, in the small chance that the bulb breaks on the floor.  Remember they last 5-7 years – so less need for handling and fumbling. Pure myth based on outdated information.

Over the last few years, the mercury content has been engineered out of the new generation of CFL bulb and continues to drop.  The manufacturers have signed a commitment to cap mercury.  It’s in everyone’s best interest.

Sure, we’re all concerned about mercury in CFLs, but according to the website, mercury in CFLs is now very small at 1.5-2.5 milligrams and after use, the “spillable” amount decreases further to 0.07.

What does this mean in relative terms?  It is 1/500th of the amount use in old fashion mouth thermometers.  It’s a fraction of the mercury content in your cavity fillings.

And… Drum roll please…most relevant comparison….

According to an article by the Illuminating Engineering Society (, two scientists from the Lawrence Berkeley National Laboratory compared the mercury hazard of a broken compact fluorescent light bulb with that of a tuna fish sandwich.  A 6oz tuna fish sandwich has 48 micrograms of mercury whereas a typical CFL breakage has 0.07 micrograms.   Read the One Big Fish Story for more insights.

In the unlikely case that you break a CFL, these broken CFL bulbs are not quite as scary as you may think. Most of the mercury in these bulbs becomes bound to the glass during use and only 14 percent gets released if the bulb breaks. Don’t use a vacuum; simply clean up with a broom, wipe the area down with a wet towel, rinse off the broom, and wash your hands.

Back to the tuna.  How’d the tuna get so much mercury in its system in the first place?   Ironically, from the emissions of coal-burning electric power plants.  More on that environmental cycle in another posting.  But just briefly, the environmental impact of incandescent is significant in terms of mercury.  Over the life of one 100-watt incandescent bulb powered by coal energy, the energy used by this one bulb puts 10 milligrams of mercury into the atmosphere that eventually works its way into our food chain, as we have seen with tuna.

So by switching out your bulbs this summer, you decrease your demand for electricity, which lightens the load on coal-burning power plants and generating less CO2 out of those tall smokestacks.

So switch today, the time is right.

Consider either one of these “bright” popular, time-tested green options.


About the author

Moose Mosely

Moose, (yes, that’s his everyday name – at least as far as we know), writes about all sorts of green living insights. Every minute, every decision we make in our lives has some impact to our personal carbon footprint, and Moose is there to share some insights on its impact and relevance and suggests healthier alternatives.