High-intensity LED streetlights emit invisible blue light that can supposedly interrupt sleep rhythms and up risk for heart disease and cancer, according to a report by the American Medical Association (AMA).
The group also warned that such light-emitting devices which are used in Los Angeles, Houston, Seattle, New York and other cities can damage drivers' nighttime vision.
Such concerns have been raised in the past, but the AMA report [PDF] will likely prompt more states and cities to re-evaluate the intensity of LED lights they install.
LEDs are considered 50 percent more energy-efficient compared to sodium lights they usually replace. Unlike typical sodium lights, LEDs spread illumination evenly and last for 15 up to 20 years, instead of just two to five years.
According to the AMA, evidence suggests that exposure to very bright LED lights at night might increase the risk for diabetes, heart disease, obesity and cancer. Such lights might also be linked to disability and discomfort glare, which can impair nighttime vision for drivers.
Scott Thomsen, a spokesperson for Seattle City Lights, dismissed the concerns about high-intensity LED lights, saying that these bulbs emit less of the problematic blue wavelengths than most televisions and computers.
Still, some experts believe that such LED lights should be regulated the same way "classic" pollutants are controlled. "There should also be regulations and rules for the pollution stemming from artificial light at night," said Professor Abraham Haim from University of Haifa. He conducted a study on the effects of "light pollution" on health in 2011.
Meanwhile, the AMA asserts that authorities should consider the use of moderate-intensity lighting rather than high-intensity LED bulbs.