Because it's energy-efficient, LED lighting is spreading into new areas, but an academic study cautions that some types of LED lights use hazardous metals.

The University of California at Irvine last week published results of a study into the materials used for LEDs in Christmas tree lights and car brake lights and headlights. After crushing these types of lights, researchers measured the contents and found they contained varying amounts of toxic materials, including lead and arsenic.

"What our study showed clearly was that some LED lights qualify as hazardous waste, depending on color and light intensity, according to federal (US EPA) regulations, and State (California) regulations. The red, low intensity fixtures that we tested exceeded lead (Pb) standards for California regulation by about 8 times, and exceed the federal regulations by about 35 times," said Oladele Ogunseitan, chair of UC Irvine's Department of Population Health & Disease Prevention via e-mail.

Right now, these products are not classified as hazardous waste, but Ogunseitan recommended that people dispatched to clean up vehicle collisions use protective gear. Homeowners should also wear gloves and masks in the case of clean-up. The copper used in some LEDs can pose health hazards to river and lake ecosystems as well if disposed of in a landfill.

Ogunseitan said that the move to LED lighting is a case in which there should be mandatory product replacement testing. He claims that the potential environmental health impacts were not sufficiently tested before manufacturers put them in products as a replacement for incandescent bulbs.

Recycling recommended for large LEDs Large LEDs bulbs with a screw-in bottom designed for home use are just coming onto the market as replacements for 40-watt or 60-watt incandescent bulbs. In addition to good efficiency and long life, these bulbs are marketed as an improvement over compact florescent bulbs because they don't contain mercury. CFLs can be returned to many retail stores or municipal hazardous waste handling services for recycling.

When LED maker Cree introduced an LED bulb it expects to come out later this year, I asked about toxins and disposal. Cree vice president of marketing Greg Merritt said that there were no hazardous materials used in its bulb and that it is expected to comply with the ROHS European hazardous material directive.

UC Irvine's Ogunseitan is testing large LED bulbs but has not yet published the results. "However, I can say that precautionary principle supports not throwing this in the regular trash for landfills," he said.

Last month, I asked the Department of Energy about hazardous materials and large LED bulbs designed for home use. A representative said that, in general, these LED bulbs do not contain toxic chemicals in any significant amount. She added that consumers will face disposal only a few times in their lives given the long projected life of LEDs, which could be over 20 years, but it's best for consumers to recycle them.

"That said, like most consumer electronics, at the end of their useful life, LEDs contain materials that are both valuable and recyclable. Where available, LEDs should be recycled using municipal recycling programs," she said.