DENVER (CBS4)- The Department of Transportation in Washington, DC will investigate one claim that a Southwest jet sat too long on the tarmac on Wednesday. The snow kept some flights from leaving Denver International Airport on time.

Some travelers told CBS4 there were problems getting planes deiced.

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DIA spokeswoman Jenny Schiavone confirms winter weather conditions existed at the airport on Wednesday.

“Around 8 p.m. last night we started to see some snow accumulation it was mostly slush, but we did see that accumulating on the roadways, runways and taxi ways,” said Schiavone.

Some airline passengers said the problem was getting deicing equipment to planes waiting on the tarmac. One passenger, who didn’t want to be identified, said the flight she was on was stuck in a line 20 planes deep.

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Because of the Traveler’s Bill of Rights, a plane must return to the terminal after waiting three hours. That means when the plane goes to the back of the deicing line when it returns to the tarmac.

CBS4’s MoneySaver Suzanne McCarroll was one of the passengers on one of those planes.

“There was much bickering I think between the pilot and the tower and we finally got up to be deiced, but by that time we had been on the plane almost seven hours. The flight from denver to pheonix is supposed to be an hour and a half,” said McCarroll.

Deicing is the responsibility of individual airlines. DIA said they had enough material to go around on Wednesday.

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“There was plenty of aircraft deicing fluid, chemical treatment for roadways, runways and that sort of thing available to us,” said Schiavone.