Have you seen a purple streetlamp? A puzzling coast-to-coast phenomenon explained.

(This story has been updated to include new information.)

Evan Lovett finds the purple streetlights alluring and troublesome as they glow over his hometown, Studio City, California. 

The area’s once yellow lights began turning purple last summer, offering “a very airy vibe, in a cyberpunk sort of way,” said Lovett, 46, the creator and host of the podcast, L.A. in a Minute. He talked about the purple lights during a recent episode.

However, the uniqueness can wear off quickly, Lovett said. After all, streetlights are supposed to help you see when it gets dark outside. The purple lights aren't particularly good at that.

The dim lights became a bit more personal after his house was broken into one night when he was out with his family in early February. He believes the purple-bluish lighting has made his entire neighborhood vulnerable.

“I’m a fan of the color purple, but I don’t want my streetlights to be that way," he said. "It’s kind of dangerous.” 

Lovett is just one of many people who have observed an odd yet atmospheric coast-to-coast phenomenon caused by faulty LED streetlights. It has led to a years-long wave of purple lights that mysteriously appear and then disappear across the nation. It's generated incorrect theories, potentially dangerous lighting and fans of an accidental aesthetic.

In Milwaukee, at least 300 streetlights installed in 2018 began taking on a purple hue in 2021. In Eau Claire, Wisconsin, some city streetlights took on a blueish-purple tint the same year, as did bulbs in the village of Schaumburg, Illinois and Palm Beach, Florida.

In all, at least 30 states have reported suddenly purple streetlights and parking lot lights, along with areas of Canada and Ireland. The first reports began in 2021 and have continued since.

Speculation abounds, and theories have included: Maybe the purple lights are more energy efficient or more wildlife friendly. Maybe they're meant to raise awareness about domestic violence. Or perhaps they make it harder for drug users to see their veins.

But the truth is that hue isn't intentional — it's the result of a spectacular, if aesthetic, failure of some LED chips. The signature purple glow has popped up, then disappeared, across the country as the lamps slowly fail and are replaced.

Safety concerns are real, especially for drivers.

"If you've driven through these areas where there's a lot of these purple street lights, you know that it's kind of glare-y and uncomfortable, which could distract the drivers and create some issues," J. Lynn Davis, a member of the Illuminating Engineering Society, said in a presentation on the lights last year.

But for some, the fleeting failure has a poetic quality.

The color "makes the ordinary look extraordinary," said Selina Román, 46, a photography professor at Ringling College of Art and Design in Sarasota, Florida.

What went wrong with the faulty purple streetlights?

The purple hue is the result of the delamination of the phosphor-silicon layer in the streetlights' LED chips.

In this case, tens of thousands of LED bulbs installed along streets and parking lots across the country, which appear to have begun delaminating around 2021.

To understand why, it's helpful to go back to the mid-2000s, when LED street lighting began to replace the sodium-vapor lamps that had been previously used. (LED stands for light-emitting diode.)

LEDs were more cost-efficient because they lasted longer and used less energy than sodium-vapor lamps. And the older sodium-vapor lamps also cast a very distinctive yellow or yellow-orange light. LEDs were meant to cast a white light.

However LED diodes don’t produce white light naturally. To get white light, it was necessary to mix other colors with blue LEDs – just as sunlight is not actually white but a mixture of all colors.

“The combination together, blue plus yellow, gives us something that approximates white light,” Davis said in an online presentation in May last year.

But something began to go wrong with some of these LED arrays beginning around 2021, when the first reports appeared of previously white streetlights suddenly casting first lavender, then violet and finally plum-colored light.

The science behind those purple streetlights

To get to the bottom of what was happening, a group of lighting experts called the LED Systems Reliability Consortium came together to research the problem.

In 2024, Davis and three other lighting researchers analyzed multiple LED modules from streetlights that were producing the purple light, using both microscopic and thermal analysis.

The group tested 28 faulty LED modules donated from the North Carolina Department of Transportation. They had been manufactured in mid-2017 and installed around 2018. The color shift began after they had been operating for three to four years.

What the researchers found was that in some of the modules, the yellowish phosphor and silicon mixture that filtered the blue light to make it white began to crack and split, eventually falling off and allowing the blue light underneath the shine through.

"It's not the phosphor itself that's failing but the binder that's attaching it to the LED, probably the silicon," said Peter Palomaki, an optics expert and chief scientist with Palomaki Consulting in Massachusetts.

The light that comes out is purple rather than blue because with the loss of some of the yellow layer, the mix of blue and yellow light tilts strongly toward blue – creating a light that appears purple, said Davis.

Although some posters online have suggested the streetlamp are emitting ultraviolet or black light, that's incorrect, Davis said.

"It's because of the combination of of blue and yellow. It's not a violet source, he said. "It's coming from the blue LED."

Who made the faulty purple streetlights?

Davis and others in the May 2024 presentation declined to name the company whose faulty LED chips they tested.

Whether the malfunctioning streetlights were made by only one company or several, and if it was just one batch or a longer production run, is not known.

In the many news articles about the LED lights being replaced in various cities Paste BN found, only one company is named – American Electric Lighting, a division of the nation's largest lighting producer, Atlanta-based Acuity Brands Lighting.

The reports came from Saint Paul, Minnesota, Sioux City, Iowa, Milwaukee, Orlando, and Tallahasee, Florida.

Neither American Electric Lighting nor Acuity Brands Lighting responded to emails or phone calls from Paste BN.

However in an interview with Business Insider in 2022, an Acuity spokesman said the effect occurred in only a small percentage of its light fixtures and that it appeared several years after initial installation. According to multiple news reports, the company is replacing all the malfunctioning lights under warranty.

In an analysis of Acuity's finances, the trade journal Insight Lighting noted that the company's warranty and recall expenses rose from $32.3 million in 2021 to $47.0 million in 2022 and $52.4 million in 2023.

Unanswered is whether, once the warranties, generally five to seven years, are no longer in place, the company will continue to replace the faulty lights.

"My fear is that there are a lot of these still working their way through the system," said Peter Palomaki, an optics expert and chief scientist with Palomaki Consulting in Massachusetts.

He tested a faulty streetlight and presented his findings in a video posted in October, 2024. From his observations and media reports, he believes the lights may fail over a fairly long time depending on local conditions.

"It's environment dependent," he said. "It could be different in Florida than in Boston. It's about light and heat and then you add moisture to the equation. It's a hard environment to ask materials to survive in."

As the lights are replaced, photographers race to record

Across the country, photographers are rapturous over the mysterious purple glow being cast by the malfunctioning streetlights that began to crop up around 2021. They call their unique gleam "mystical" and "magical."

In Los Angeles, photographer Willem Verbeeck cruises the streets scanning for purple streetlights at least three nights a week. For him, the subtle nature of purple captures an essence that used to be seen in old movies.

The “deeper and darker the purple, the better,” he said. The purple lighting doesn’t illuminate, he said. Instead, the color “sits on things and doesn’t show anything, not the traditional way a streetlight should,” he noted.

With cities working to replace the bulbs, the photographers are busy trying to capture the fleeting moment.

Verbeeck's nearly two-year journey to photograph areas with the purple lights has taken him across L.A. up to the Hollywood Hills, near downtown and over to the beach. For him, it's “going on a treasure hunt.”

Recently, his purple light treks have taken him to industrial areas like the Port of Long Beach, where the lights don’t get immediately fixed and there aren’t many residential complaints.

“I think it’s incredibly eerie and unsettling,” he said. “It’s not a totally uncomfortable experience, but it feels like you are in a back alley or a place you’re not supposed to be, that’s the feeling I get.”

For Román, seeking out the mauve light has became a passion project and resulted in a photo collection she called “A Bad Batch”

Recently she saw some of purple hued lights at the rest areas off the Skyway Bridge during her commutes from Tampa to Sarasota. 

“The purple lights take an otherwise bland, average scene at night and creates something mystical and magical," she said. “I felt like I was in a race to get them before people started complaining and they would get fixed.”