Steve Neavling

An incessant, high-pitched hum coming from a nondescript FBI building in Virginia is driving neighbors crazy, the Washington Post reports.

“You’ve never stood next to such a loud building,” Tom Jackman wrote for the Washington Post. “It sounds like a helicopter is hovering a block away – a helicopter that never goes away. It just keeps buzzing, 24 hours a day.”

The loud noise comes from 23 “dry cooler” air-conditioning units atop the three-story office building. Each with 10 fans, the units make 230 “high-velocity whirring noises,” Jackman wrote.

The building houses the FBI’s Terrorist Screening Center, which compiles the no-fly list and other national security information.