The Transportation Department on Tuesday levied $175,000 in civil penalties against Continental Airlines, ExpressJet and Mesaba Airlines for their roles in the Aug. 8 overnight tarmac delay of a Continental Express flight in Rochester, Minn.

The fines are the first DOT penalties against airlines for extended tarmac delays.

Although they acknowledged no wrongdoing, Continental and ExpressJet (operator of the Continental Express flight) agreed to a penalty of $50,000 each.

Half of the amount is scheduled to be paid within a month, with the remainder set aside to establish or strengthen rules, policies and operations to prevent this kind of delay again.

According to the consent order, ExpressJet maintained it had tried to prevent a tarmac delay but was denied gate access by Mesaba, the gate operator at Rochester Airport.

Mesaba acknowledged no wrongdoing but agreed to a $75,000 penalty, half to be paid within a month and the remainder to be used to implement policies or training to prevent another similar incident.

Mesaba said ExpressJet’s desire to get the passengers off the plane was "ambiguous" throughout the evening, according to the consent order. ExpressJet officials, Mesaba maintained, seemed more interested in continuing the flight.

Still, the DOT said that Mesaba’s continued incorrect contention throughout the night – that the ExpressJet passengers could not get off the plane and enter the terminal because no Transportation Security Agency representatives were there – was a "significant cause of the 47 passengers remaining onboard."

"Misinformation provided by the Mesaba station agent demonstrated an indifference to the passengers and amounted to an unfair and deceptive practice," the DOT said.

The DOT said ExpressJet engaged in an unfair and deceptive practice when it failed to alert higher-ranking airline officials about the delay, as they were supposed to according to airline’s policy. The DOT also said ExpressJet added to the delay by trying to complete the flight.

Although Continental did not operate the delayed flight, the DOT said Continental was ultimately responsible for passengers on flights that it markets.

Continental argued that it has tarmac delay policies in place and that partners such as ExpressJet agree to follow them. Continental also said that its customer-service commitments – which spell out those policies to passengers – are voluntary and not subject to the DOT's enforcement authority.