Turner Broadcasting System apologized to Boston-area residents Friday after a marketing campaign for its subsidiary Cartoon Network caused a major security scare.

Turner chairman and CEO Phil Kent issued the mea culpa in full-page ads in Boston newspapers for "the confusion and inconvenience" caused.

Dozens of electronic signs like this one that hung beneath an overpass in Boston sparked the bomb scare.
(Todd Vanderlin/Associated Press)

Highways, bridges and river traffic were shut down in several areas Wednesday while police checked out blinking electronic signs that some people thought were bombs. The signs were actually advertisements for the show Aqua Teen Hunger Force.

  "We never intended this outcome and certainly did not set out to perpetrate a hoax. What we did is inadvertently cause a great American city to deal with the unintended impact of this marketing campaign. For this, we are deeply sorry," Kent said.

"Our focus today and in the days ahead is on demonstrating to you the sincerity of our desire to do what is right. What happened in Boston is a humbling reminder that reputation is something we earn every day. We are working to regain your respect," the letter said.

Turner did not notify officials of the publicity stunt until 5 p.m., nearly four hours after the first calls came in, state Attorney General Martha Coakley said.

Mayor Thomas Menino estimated the costs of the afternoon-long security scramble to be $500,000 US in Boston alone. The Massachusetts Bay Transportation Authority, state police and the cities of Cambridge and Somerville could be on the hook for another $500,000, according to officials.

Charged man 'freaked out'

Menino said TBS had agreed to pay for the costs, the Boston Globe reported on Friday. Turner spokeswoman Shirley Powell told the Boston Herald that company officials were still in discussions about reimbursement.

"We are having lots of conversations with the appropriate officials in Boston, including the mayor," Powell said.

Two Massachusetts men were arraigned Thursday on charges of disorderly conduct and placing a hoax device.

Peter Berdovsky, 27, of Arlington, Mass., and Sean Stevens, 28, of Charlestown, Mass., worked together to place the devices, Coakley alleged in a press release.

Berdovsky told the Globe earlier Wednesday that he was an artist and installed the devices for an advertising company hired by Turner. He described himself as "a little kind of freaked out," the Globe reported.

The blinking electronic signs, some of which had protruding wires, generally depicted a cartoon character raising his middle finger in an obscene gesture.

They were placed in nine other U.S. cities without incident, but caused a major stir in Boston, where officials found 38 of them on bridges, a subway station, a hospital, Fenway Park and other high-profile spots in and around the city.

With files from the Associated Press