It was nearly midnight in late April when Lynell Morris’s husband, Michael, returned home after a shift at work.
As he fumbled his keys, the motion-sensing light on their front doorstep flicked on. His eye caught a glint of gold: a .22 bullet on his doormat. It seemed odd as he and Lynell own a different-caliber firearm. Nevertheless, he brought it inside and set it on their kitchen table.
A few days later, he remembered to ask Lynell about it. Immediately, she yelped, “Politics!” Neither Lynell nor Michael is running for office. But over the last few months, Lynell had become enmeshed in local politics after a cryptocurrency mine set up shop in their town of Murphy, North Carolina, in September 2021. “Mine” is a misnomer, as these facilities are clusters of computing units, solving complex problems to help transact and generate virtual currency, with large—and noisy—fans to cool them.
Sitting in the foothills of the Appalachian and Blue Ridge Mountains, Murphy is a lush oasis promising an uninterrupted soundtrack of nature, and attracting those who value that quiet. Within weeks of when the mine began running, angry residents started complaining about the incessant noise on Facebook and Nextdoor. They likened this new, pervasive sound to a highway, a jet engine on the runway, or a semi idling in their driveway, and said it was disrupting their sleep and eroding their sense of peace.
The Morrises are lucky. They only hear the mine from their home when there’s no other noise outside. But Lynell was frustrated by her neighbors’ stories and began speaking out on their behalf at bimonthly county commissioner meetings. “I take up for the underdogs,” she says. Lynell has always been a leader. Before moving to Murphy three years ago with the intent to retire there, she ran a small business with her husband. And, as she puts it: “I was blessed with a mouth.”
Lynell ran her mouth on April 18, at the Cherokee County (Murphy is the county seat) board of commissioners meeting. More than six months had passed since the mine began causing a disturbance, and she was fed up with the lack of transparency from her elected officials, who had yet to act upon the concerns of their citizens. Residents have three minutes to make a statement during the public comment period at these meetings. Lynell took the podium and spoke for more than 20 minutes, pressing the commissioners on why they’re backing the mine and what they’re planning to do to mitigate the noise.
After the bullet appeared on her doorstep, she wondered if she had said too much. “I’m a Southern girl. I don’t scare easily,” she says. “It was a threat, nevertheless.”
The Sound of Cryptocurrency
Follow Highway 64—or as the residents call it, the four-lane—east from town for about three miles. Turn right on Harshaw Place and left on Harshaw Road at the stop sign. Drive parallel to the highway for about half a mile, and you’ll see it on your left: large white boxes housing blue containers in a cornfield, partially surrounded by a gray wall. It looks out of place in western North Carolina, something so modern.
As you approach the mine, which is owned by the San Francisco-based firm PrimeBlock, you begin to hear the roar. During the day, its low-frequency hum—which, directly outside, may go up to 95 decibels—can make it seem like you’re next to a running motorcycle. From the mine, roads weave like a spider’s web. Harshaw Road continues east. Back at the stop sign, Mulkey Place goes straight. The two are bisected by Club House Road, which then turns into Poor House Mountain Trail. All the streets wind with hairpin turns up into the lush hills, splitting into side streets. Many houses off Harshaw, Mulkey, and Poor House Mountain surround what used to be the 18-hole Cherokee Hills Golf and Country Club, which closed at the end of 2016.
Sound travels in waves and tends to travel farthest in open landscapes. And low-frequency sounds, like the rumble from the crypto mine, travel farther than high-frequency sounds (think: a scream, or nails on a chalkboard) because the longer waves of a low-frequency noise cover more ground before losing energy. In Murphy, residents who can hear the indelible hum most prominently live near an unobstructed path from it. During winter, the noise gets worse without leaves on trees to help absorb the sound. But year-round, residents living up to a mile away from the mine can hear it.
In December, Lynell and fellow resident Cyndie Roberson started a private Facebook group for people to share their experiences and grievances. In a town of about 1,855 people, up to 800 families live within a mile of the mine.
Many residents have installed apps on their phone to track the sound levels. It’s so loud that Gene Johnson, whose ears were damaged during his stint in the military and who now wears hearing aids, can still hear the low rumble when the aids come out. He lives on Beaver Ridge Trail, which breaks off Harshaw immediately after you pass the mine. It’s so loud that Mike and Jennifer Lugiewicz, who lived two houses down from the mine, could watch but not hear their neighbor mow their lawn. (They have since moved to be farther from the mine.) The din can hide the sound of cars, so now Shannon Coleman helps her mom, who lives a half mile past the mine on Harshaw, retrieve the mail from her box across the street on a blind turn. Her mother, who is legally blind, can’t discern the sound of an oncoming car from the sound of the mine, and fears getting hit.
The noise, residents say, is especially terrible at night and early in the morning, when it wakes them up. Some say it’s caused them to become depressed and anxious. They’ve been showing up, as Lynell has, to county commissioners meetings bedraggled, frustrated, and angry that their elected officials have done very little to protect their health.
Patricia Callahan lives in the townhouses on Club House Road. Her unit is the closest to the mine, about a quarter mile away as the crow flies.
Callahan moved to Murphy three years ago, after completing a work-study program at the John Campbell Folk School, an artisan school for adults just outside Murphy, in Brasstown. Her youngest had just left for college, and Callahan was looking for a spot where she could retire. She was taken by Murphy’s art scene, but more importantly, the tranquility, and decided to buy in Murphy. After her real estate agent showed her the townhouse, Callahan sat outside at its picnic table and thought, “I have found my peace and quiet.”
Those qualities were crucial for Callahan. A car accident 15 years ago left her with a brain injury, post-traumatic stress disorder, and depression. “I arranged my life to keep my stress low,” she said. “My whole body will go into a hypervigilant fight-or-flight mode when I’m around too much noise.”
When the mine came online last fall, Calla han’s way of life was upended. She used to open the windows at night to cool her bedroom (she prefers not to use air conditioning because she lives on a strict budget), but she must close her windows now to lower the noise. Even that, along with wearing noise-canceling headphones, is not enough. The only time she’s been able to get a good night’s sleep is when she’s in a hotel or camping.
The noise is a constant, Callahan says. “It’s more than just my hearing. It affects my whole body, triggering PTSD symptoms,” she says. Many older residents with underlying health issues who have retired in Murphy express a similar sentiment: The noise and sleep interruptions caused by the mine are making their conditions worse.
Callahan says she can’t sell her house to move somewhere quieter. “Nothing is within my budget,” she says. “I’m trapped here.”
Mining New Money
Cryptocurrency is a digital form of currency that can be used like cash or a credit card. Unlike the U.S. dollar, there is no central authority that prints more coins, or maintains the value of a cryptocurrency. This lack of oversight and regulation is appealing to many who wish to grow their wealth without traditional banking institutions.
Bitcoin became the first viable cryptocurrency in 2009, and over the last 13 years, demand for cryptocurrencies has only skyrocketed. Now, there are more than 10,000 cryptocurrencies valued around $1 trillion in total, and a 2021 Pew Research study found that one in six Americans use them. “There is a general movement of making finance more for the people,” Matteo Benetton, PhD, an assistant professor of finance at University of California, Berkeley, says of cryptocurrency’s appeal. Cryptocurrency mining is computers solving complex algorithms to record crypto transactions that prevent people from spending their currency more than once. After a certain amount of work, a mine is paid in newly created cryptocurrency. This computing relies on an astronomical amount of power. The Murphy mine, according to Scott Wade, the head of operations at Exponential Digital, the company that operates the mine and was acquired by PrimeBlock last January, uses anywhere from 5 to 15 megawatts annually, enough to power up to 13,500 homes. (A gaming laptop, by comparison, would use 0.02 megawatts running year-round.)
Up until 2021, most of the world’s crypto mines were housed in China. But when the country banned the use and mining of cryptocurrency that fall—largely because of the Chinese government’s fear that cryptocurrencies are a gateway to financial crime and have a negative impact on the environment—miners flocked to the U.S. According to the Bitcoin Mining Map developed by the University of Cambridge in the U.K., the U.S. now makes up the majority of the total global hashrate, or the computational power processing cryptocurrency transactions.
In the U.S., crypto companies generally set up shop in places like the Finger Lakes region in upstate New York, eastern Washington, South Dakota, and towns like Murphy along the Tennessee Valley. They all offer cheap electricity, and often, mines can be built in repurposed factories.
Not only is noise pollution an issue, but the annual electricity use worldwide from exclusively mining Bitcoin—just one type of crypto currency—is extensive. Some studies estimate it can even exceed that of entire countries. This overall higher community electricity use raises the cost for residents.
The Pain of Noise Pollution
Because cryptocurrency is relatively new, there are few peer-reviewed studies that specifically link it to how its mines affect human health and the environment. Twenty-two state legislators have written to the EPA to monitor the environmental impact of mining cryptocurrency. But noise is the primary complaint in Murphy, and plenty is known about how loud, persistent, low-frequency sounds can lead to a host of problems.
In the 1970s, the U.S. Environmental Protection Agency’s Office of Noise Abatement and Control recognized noise as a pollutant and began taking steps to limit community exposure. Through the now-defunct office, researchers determined that, to ensure their health and welfare, residents shouldn’t be exposed to more than an average of 55 decibels over the course of a day. Anything higher, in terms of sound level or length of exposure, could increase an individual’s chances of hearing loss. Even though the world around us has gotten noisier since then—particularly in cities and largely due to industrial noise—our ears can’t adapt accordingly, says Deanna Meinke, PhD, an audiologist who studies dangerous decibels at the University of Northern Colorado in Greeley.
Over the last few decades, researchers have seen that prolonged exposure to noise can lead to high blood pressure and other cardiovascular issues, and even exacerbate mental health disorders. What’s more, noise pollution can be more detrimental at night, when our bodies are much more vulnerable to sounds during sleep.
And sound-level guidelines for health impacts beyond hearing loss don’t yet exist. “We don’t have limits for a noise level that would prevent heart attacks, or prevent high blood pressure, or prevent depression,” says Rick Neitzel, PhD, a noise pollution expert at the University of Michigan.
In 2020, an international team of researchers published a study in European Heart Journal where they followed about 500 healthy adults for five years. They found that every five-decibel increase over a baseline 45 decibels for a 24-hour span was associated with a 34 percent jump in heart attacks, strokes, and other cardiovascular issues.
And in the early 1990s, the Federal Aviation Administration (FAA) sponsored several studies to determine how loud an airport could be without making residents seriously annoyed. They found that about half of the residents reached that threshold of annoyance when exposed to an average of 75 decibels over a 24-hour period, although they didn’t characterize how that manifested in health impacts. But about 20 years later, a group of German researchers tracked over 2,300 residents who lived in the flight path of Frankfurt Airport, and found that the individuals who reported to be “strongly annoyed” by the noise were twice as likely as others to feel depressed or anxious.
The annoyance and resulting stress that Callahan and her neighbors face shouldn’t be discounted, says Neitzel. “Annoyance is a huge byproduct of noise exposure, and we don’t really understand how important that is in terms of putting someone at risk.”
When noise becomes a stressor—as it has been in Murphy—it activates the adrenal system, which not only responds to stress but also regulates an individual’s immune and cardiovascular system. “It’s not good to spend 8, 10, or 12 hours a day in that condition,” Neitzel says. It can drive up heart rate and blood pressure, and cause problems down the line.
As soon as the mine came online, residents in the surrounding neighborhood began noticing changes in animal behavior. Ronny and Kathy Williams, who live atop Poor House Mountain Trail, lament the decline of birds in their backyard, where they keep multiple feeders. “We’ve seen very few goldfinches this year. The house finches came and went. And I’ve only seen one Carolina wren this year,” Ronny says.
Meanwhile, Phyllis Cantrell, who lives about as far from the mine as the Williamses, has noted that hawks and eagles no longer nest nearby. The hummingbird feeders on her deck she used to refill four times a day are now going three days before she replenishes them. The area near the mine used to be prime habitat for wild turkey and deer. Now, they’re moving farther up the mountains. Morris, for instance, has recently found deer in her backyard for the first time.
A herd of horses that live on a patch of land across from the mine on Harshaw have been trying to flee more frequently, too, according to the Lugiewiczes, who live across from where they’re kept. On a warm weekend last December, on a day when the fans from the mine were especially loud, Jennifer and Shannon Coleman spent an hour trying to wrangle the horses—who seemed spooked by the noise—all the while shouting over the din, standing just five feet away from each other. And dogs begin howling, says Cantrell, when the mine is especially loud at night.
Research shows that hundreds of animal species are affected by noise, says Clinton D. Francis, PhD, an evolutionary ecologist who studies noise pollution at California Polytechnic State University, San Luis Obispo.
The ability to perceive sounds and respond is a part of a “universal threat detection system” across vertebrates, he says. “Hearing is used to passively listen for threats while we’re doing other things.”
The impact of noise pollution is perhaps best characterized for birds. They may modify their songs to be at a higher pitch or sing more frequently to stand out amid the noise. Some field research shows that about a third of birds may completely leave an area because of noise pollution, with major ecological consequences. In 2012, Francis and his colleagues published a study that showed low-frequency industrial noise from gas wells and compressors (clocking in at around 95 decibels) reshaped areas of the Rattlesnake Canyon Habitat Management Area in northwestern New Mexico. Birds there are critical in dispersing seeds of the Colorado pinyon pine. And now, some preliminary research from Francis’s group suggests that noise pollution may lead to inheritable changes in specific species and populations. In other words: Noisy enterprises like crypto mines can alter the wildlife near it for generations to come.
But Francis is heartened by the fact that when the source of noise is removed, animals reclaim where they once lived. Think back to the early days of the COVID-19 pandemic, for instance, when the songs of the white-crowned sparrows in San Francisco grew more frequent when the din of the city subsided, or lions napped along traffic-free roads in South Africa.
Lax Zoning Laws and Few Answers
Despite the annoyance, the deleterious health effects, and the damage to the ecosystem, there’s no legal protection for the residents of Murphy due to scant zoning laws in Cherokee County, which would otherwise protect residential areas from industrial development. Already, there are three mines in the county, and citizens fear more may be coming.
Some Murphy residents have left because of the noise from the mine. Others who have put their life savings into their idyllic mountain home have no choice but to fight for change and show up to the commissioners meetings in droves. So far, the residents’ concerns about noise mostly have fallen on deaf ears. They’re also frustrated by the lack of answers from their five commissioners as to how the mine ended up there in the first place. They’re trying to get their elected officials to enforce a 1999 county ordinance under which perpetrators are fined $50 a day for sustained noise above 50 decibels. But the commissioners say that the ordinance is unenforceable without the zoning laws that Cherokee County lacks.
And without zoning laws, it’s impossible for anyone to find a legal standing to hold anyone accountable. In Limestone, Tennessee, where the cryptocurrency company Red Dog set up shop, residents had recourse because Red Dog violated an existing zoning ordinance. That county sued and won. The mine is set to shut down by the end of 2024, pay associated penalties, and relocate away from a residential area.
The Cherokee County board of commissioners—particularly Dan Eichenbaum, Gary Westmoreland, and Randy Phillips, who locals refer to as “the triad” for their similar voting patterns on controversial issues—are not keen on changing the status quo. None responded to comment on this story. And amid the calls for zoning reform, a quieter contingent of Murphy residents don’t want any government interference in land use or rights.
Since the Murphy mine was set up last fall, it was partially enclosed by wall sections in February, but locals say that only made the sound worse, as the openings between the walls funnel sound in very specific directions. Wade, of Exponential Digital, said that this partial enclosure helps them “maintain and preserve natural cooling and airflow, resulting in a more energy- efficient operation while further mitigating sound.” Moving forward, Wade says, the company will work closely with the commissioners to ensure the facility doesn’t generate more noise.
For now, Morris hopes that this year’s election will help, as the residents can vote for someone who will make decisions in their interests. “Until you get the commissioners behind this and really start pushing for it, change isn’t going to happen,” she says. “It starts with them.”
Since the bullet on her doorstep, Morris has taken a backseat at the meetings, but she’s still attending and staying engaged. Already, not even a year out, she’s tired, and looking forward to what—eventually—could come after the mine. For her, it means peace and quiet, and the paradise that Murphy promised.
Wudan Yan is a journalist, podcast producer, and entrepreneur based in Seattle.