Dim Prospects

Fluorescent bulbs and light-emitting diodes (LEDs) may be energy-efficient, but their high metal content could make them more toxic to the environment than traditional incandescent bulbs when thrown out.

Government agencies are urging consumers to replace their energy-hogging incandescent lightbulbs with more efficient and longer-lasting compact fluorescent lamps (CFLs) and LEDs. CFLs, for example, require only about 30 percent as much energy as incandescent bulbs and last 10 times longer. But what happens when these “green” bulbs are used up and thrown in the garbage?

A research team studied the three types of bulbs and found that CFLs and LEDs contain more metals such as copper, lead, and zinc. Because of these high metal levels, the CFL and LED bulbs (but not the incandescent bulb) are considered hazardous waste according to US federal and California rules.

The researchers then analyzed how environmentally harmful the bulbs’ metals might be. Since incandescents last only about 10 percent as long as CFLs and 2 percent as long as LEDs, the team compared the effects of 50 incandescent bulbs to those of five CFLs or one LED. The CFLs were still 3 to 26 times more potentially toxic than the incandescents, while the LED was 2 to 3 times more potentially toxic.

“[I]t is urgent to develop more environmentally friendly products by reducing the metal content to below the threshold limits or by replacing the hazardous metals with safer alternatives,” the authors write in Environmental Science & Technology. Recycling programs could also allow these metals to be reused instead of tossed in the trash. Roberta Kwok | 2 January 2013

Source: Lim, S.-R. et al. 2012. Potential environmental impacts from the metals in incandescent, compact fluorescent lamp (CFL), and light-emitting diode (LED) bulbs. Environmental Science & Technology doi: 10.1021/es302886m.

Image © amasterphotographer | Shutterstock.com



  • KG January 2, 2013 at 7:34 am

    Interesting. Part of the argument for CFLs, despite the high Hg levels, has been that the high Hg levels are offset by the fact that they require less electricity to use. This means that less Hg is pumped into the atmosphere since such a large proportion of electricity is produced by burning Hg-laden coal.

    My quick read of the original paper suggests that this effect wasn’t taken into account. I’d love to know how significant it is (or is not).


  • Michel colville January 2, 2013 at 10:07 am

    Our local Ace hardware stores take the bulbs for recycling now. I have never asked them what they do with. I will enquirep and send you the response.

    Michel Colville
    Missoula, Mt


  • sue January 2, 2013 at 3:13 pm

    The figures comparing incandescent to fluorescent and LED need to include the toxic effects of increased generation of energy when generated by coal, nuclear and other fossil fuel sources. Mercury pollution generated by coal fired plants is huge.


  • UrbanAgProducts January 4, 2013 at 7:32 am

    A total picture that looks at carbon footprint created by producing and consuming (so manufacturing, increased packaging, increased shipping and disposing) of a product that has a short life cycle and a high energy foot print or a product that is environmentally more toxic and reliant on heavy metals? Hmmmm. Can we actually win?

    Maybe the answer is leave the lights off:)


  • Jan Koza January 6, 2013 at 1:27 pm

    I’ve been concerned about the use of mercury in household lighting, mainly because of it’s ease of use and potential abuse in dispossal. I’m not sure that the concept and premise is in our best interest and I can see the value in conservation; but does that out weigh the health risks? I don’t think that mercury is a new use in lighting because industry has been using mercury vapour lighting for many years – 300, 500 & 1000 watt lamps were not uncommon. With the word mercury used in describing the bulb I think it would be safe to say that mercury is used in it’s manufacture and make-up. What’s disturbing to me is the disposal of all these bulbs – there was no controls put in place nor any known attention to the dangerous properties they contained. How did we manage to go so long without questioning the use of mercury in production before. Speaking of manufacturing; what about the employees who must be exposed to these agents while working in that environment? The magnitude of exposure surely has to be greater than just breaking one bulb household bulb?


  • James January 7, 2013 at 12:49 pm

    When did the expriment actually happen.


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