MARA Bitcoin Mining Data Center, Granbury, Texas

The bitcoin mining data center that MARA Holdings, formerly Marathon, built in 2022 beside the Wolf Hollow power plant outside Granbury, in Hood County, Texas, has drawn noise complaints from its neighbors ever since. The site runs about 60,000 computers cooled by industrial fans that residents of the rural Mitchell Bend area say shattered their peace and quiet.

Hood County Constable John Shirley measured 91 decibels coming off the site, a level the Centers for Disease Control estimates as roughly between a lawnmower and a chainsaw. Texas law treats 85 decibels as the limit for reasonable noise, and over 2024 Shirley documented more than 35 breaches of it. The CDC says two hours at 90 decibels can damage hearing.

More than 40 residents reported illness, including hypertension, heart palpitations, chest pain, vertigo, tinnitus, migraines and panic attacks, with at least ten people seeking emergency or urgent care. Larry Potts, a retired pastor of 77, was rushed to the hospital in February when his heart gave out, kept alive by an external pacemaker and diagnosed with third degree atrioventricular block. Five-year-old Indigo Rosenkranz suffered a seizure on July 6 and was taken to the emergency room.

German cardiologist Thomas Munzel, who studies noise and the heart, said the European Environment Agency "tells us that everything above 55 decibels is making us sick," and called levels of 70 to 90 decibels like torture. In 2024, the company said it would replace most of its air-cooled containers with immersion cooling by the end of that year, while acknowledging the risk of converting the technology at that scale. A sound wall built in 2023 at a cost of $1.9 million had made little difference by then.

Shirley's fines of $500 each came to about $17,500, against Marathon's revenue of $165 million in the first quarter of 2024, and the company asked for a jury trial to overturn the citations. Since then MARA has built a taller, 24-foot wall and moved 67% of its cooling fans to a liquid cooling system, but residents say the noise remains disruptive.

Because Texas counties lack authority to enforce noise limits, residents tried to incorporate the roughly two-square-mile community of about 600 people as the City of Mitchell Bend so it could pass a noise ordinance. MARA sued to block the election, a judge let it proceed, and on November 4, 2025, 62% of the 138 voters rejected incorporation. "We're pleased that Hood County voters saw through the sham incorporation effort and rejected it at the ballot box," a MARA spokesperson said.

That leaves the courts. Citizens Concerned About Wolf Hollow, represented by Earthjustice, sued MARA in state court in October 2024 claiming the mine is a private nuisance. After the court rejected MARA's bid to dismiss, the group filed a motion in September 2025 to force the company to hand over its noise records; no ruling on that motion has been published.