You’d be hard-pressed to find a public place that welcomes smokers nowadays in Denver. The city has even recently moved to ban smoking and vaping along the 16th Street Mall.

However, like a relic from another era, Denver International Airport still has a dedicated indoor space, the Smokin’ Bear Lodge Smoking Lounge on concourse C, where passengers can light up before their flight.

Three DIA smoking lounges have already closed, and the Smokin’ Bear space will shutter when its lease expires in 2018, according to the Denver Business Journal, but DIA still landed on a health list that some call the smoky list, compiled by the Centers for Disease Control and Prevention.

The CDC study looked at the smoking policy of the 50 busiest airports in the world, and Denver was one of just three in the U.S. (and 27 worldwide) without a smoke-free facility. McCarran International Airport in Las Vegas and Hartsfield-Jackson International Airport in Atlanta were the other two U.S. airports to join DIA as smoking facilities.

To be considered a smoke-free airport, a facility must “completely prohibit smoking in all indoor areas,” the study said. Even though smokers are separated, in designated or ventilated smoking areas, from non-smokers, “studies have documented that secondhand smoke can transfer from designated smoking areas into nonsmoking areas in airports, where nonsmoking travelers and employees can be exposed,” the study read.

“In addition to subjecting nonsmoking travelers who pass through these areas to involuntary secondhand smoke exposure, designated or ventilated smoking areas can also result in involuntary exposure of airport employees who are required to enter these areas or work near them,” the study said.

“Smoke-free policies substantially improve indoor air quality and reduce secondhand smoke exposure among nonsmokers.”

DIA has plans to eventually become a smoke-free facility, the Denver Business Journal reports.