Washington ? Federal regulators Thursday proposed $495,000 in indecency fines against Clear Channel Communications for broadcasts by Howard Stern, prompting the nation’s largest radio chain to drop the country’s best-known shock jock.

Clear Channel suspended Stern in February from its six stations that carry his program, which regularly features graphic sexual discussion and humor. It decided to make the move permanent after the Federal Communications Commission cited the chain for 18 alleged violations from Stern’s April 9, 2003, show.

“Mr. Stern’s show has created a great liability for us and other broadcasters who air it,” said John Hogan, president of Clear Channel Radio. “The Congress and the FCC are even beginning to look at revoking station licenses. That’s a risk we’re just not willing to take.”

In a statement posted on his Web site, Stern said he was not surprised by the fine. He characterized it as furtherance of a “witch hunt” against him by the Bush administration.

The FCC investigation was prompted by a listener in Fort Lauderdale, Fla., who complained about a Stern program that included discussion of sex accompanied by flatulence sounds.

Federal law bars radio stations and over-the-air television channels from airing references to sexual and excretory functions between 6 a.m. and 10 p.m., when children may be tuning in.

The FCC imposed the maximum fine of $27,500 for each of 18 violations on six Clear Channel stations: WBGG in Fort Lauderdale; WTKS-FM in Cocoa Beach, Fla.; WTFX-FM in Louisville, Ky.; KIOZ in San Diego; WNVE in Honeoye Falls, N.Y.; and WSDS-FM in Pittsburgh.