The exodus of advertisers fleeing from Rush Limbaugh may finally be taking a toll on his radio show.

Liberal watchdog group Media Matters noticed that on at least two occasions on Thursday, Limbaugh's flagship station in New York, WABC, broadcast several minutes of dead air during commercial breaks.

There were over two and a half minutes of dead air leading into the show and then another minute of dead air during the first hour of the program.

In a statement on his website over the weekend, the conservative radio host said he “sincerely” apologized to Georgetown University law student Sandra Fluke, who he had called a “slut” and a “prostitute” after she testified before Congress about the need for contraception coverage at colleges and universities, even if they are owned by religious institutions.

According to Media Matters' count, at least 48 advertisers had cancelled their ads by Thursday afternoon.

Limbaugh played the controversy down on Wednesday, telling listeners that "everything's cool."

"Nobody is losing money here, including us, in all this," he said. “[The advertisers] are not canceling the business on our stations. They’re just saying they don’t want their spots to appear in my show. We don’t get any revenue from ‘em anyway. The whole effort is to dispirit you.”

AdAge determined that nearly half of the 69 commercial spots during Thursday's show had been replaced with public service announcements.

Dead air happens when a radio or television station fails to broadcast anything over a period of time. It is generally considered to be one of the worst things that can happen in broadcast industry.

One of the most famous examples of dead air happened when anchor Dan Rather decided to walk off the set of the CBS Evening News in 1987 because he was angry about the show being preempted by a tennis match. For six minutes, no picture was transmitted, which was considered unprecedented at the time.

According to The New York Times, the network and its affiliates were flooded with calls from angry viewers.

Listen to this audio from The Rush Limbaugh Show, broadcast March 8, 2012 and uploaded by Media Matters.