New research shows LED street lights cause health problems

SEATTLE -- New research shows LED street lights have harmful effects. The American Medical Association released a warning earlier this year against high-intensity street lights like those found in Seattle could cause a host of medical issues, including obesity.

In the AMA report, researchers said “blue-rich LED streetlights operate at a wavelength that most adversely suppresses melatonin during night. It is estimated that white LED lamps have five times greater impact on circadian sleep rhythms than conventional street lamps. Recent large surveys found that brighter residential nighttime lighting is associated with reduced sleep times, dissatisfaction with sleep quality, excessive sleepiness, impaired daytime functioning and obesity.”


“I had to look at the clock twice and look outside twice,” recalled Cody Spencer on Thursday morning. “I thought, oh, it’s those darn lights they put up last night.”

Spencer lives in Alki. His street is getting overhauled from high pressure sodium lights to LED.

He said it was so bright, “I just thought the sun had come out early.” He said the streets are noticeably brighter, but the light does not travel across the sidewalk.

“It definitely cuts a lot of the light pollution that kind of goes into these houses from the lights before,” he said.

Seattle requires that their LED street lights come equipped with shields that can direct the light away from homes and into the street. A flexible neck on the street lamp itself allows for custom focus.

“All of our lights have the ability to tilt to get the light off of a home,” said Edward Smalley, a manager at Seattle City Light. “These are just requirements, these weren’t available when we first started looking at LED lights.”

Seattle started replacing their high pressure sodium lights back in 2009 to LED. They say they are cheaper for the city, saving energy and the environment.

“Rather than lasting three to four years, the lamp source in the LEDs can last 12 to 15 more years,” said Smalley.

When an LED lamp burns out, they can be easily tossed out. A high pressure sodium bulb can’t, because it contains components toxic to the environment.

“With each lamp that came out, we had a team at Seattle City Light that takes those lamps, bags them in a certain way and disposes of those as hazardous waste,” said Smalley.

“I am very much into environmental sustainability and I know that LEDs are much easier to dispose of and recycle than the high sodium bulbs before,” said Spencer.

There are a many positives to LED street lights that the AMA concedes are notable. But the major problem they cite comes from the blueness of the LED. They said it can disrupt sleep patterns, decreasing the melatonin that is produced in the brain.

“We have to look at that information and take it really seriously,” said Smalley of the research.

Some cities are reducing their LED bulbs from 4,000 Kelvin to 3,000K, referring to the color of the light.

The lower the Kelvin, the less blue that is being emitted. Seattle said that 3,000K was not available when they made the switch to LED seven years ago. The lights they use are 4,000K, but the improvements to the engineering of the lamp itself they said help.

“If you’re going to walk into a 7-11 at night,” explained Smalley, “it’s going to be 20 times what you just experienced on those light levels on the street at night.”

Seattle said they will consider 3,000K lights moving forward, but do not have immediate plans to replace their 4,000K lights.

They said LED lights are safer for pedestrians and drivers, than the older alternative.

“They are definitely a lot brighter, so it’s a lot safer at night time,” said Spencer.