Local Public Broadcasting Service (PBS) stations could pull in hundreds of millions of dollars this year by selling their airwaves to the federal government, raising worries that pockets of the US could lose their access to public television.

The Federal Communications Commission is poised to buy broadcast licenses from local TV stations, aiming to free up airwaves and resell them to wireless provider. Major station owners have agreed to participate in the FCC auction. So have some of the nation’s roughly 350 public-TV stations, whose broadcasts currently cover about 99% of the U.S. population. It isn’t clear just how many stations have signed on, because the process is confidential under FCC rules. The stations that sell their airwaves could go off the air, potentially redrawing the map for public television and its audience. The Public Broadcasting Service, which produces programming for its independent member stations, has little say in the matter, and won’t get any of the sales proceeds. Public-TV advocates fear the auction will deprive some Americans of their free access to noncommercial television. “We’ve been concerned about that for quite a while, and still don’t have a good handle on what our exposure is there,” said Patrick Butler, president of the Association of Public Television Stations, referring to the possibility that some stations could leave the air.