The construction costs on what was supposed to be a “fixed-price” contract on the troubled Port Mann Bridge has ballooned hundreds of millions of dollars, according to a government watchdog group.

Building the bridge, interchanges and overpasses in the project resulted in some $423 million more paid out to the principal contractor – a huge amount that would have scandalized previous B.C. governments, said Integrity BC’s Dermod Travis.

“First of all, you could buy all of the Fast Ferries for the difference between the fixed price and what they’ve paid out,” he said.

It’s the latest issue for the $3.3-billion bridge, which pelted drivers with “ice bombs” the first winter after it opened, and now can’t attract enough drivers to pay its bills through tolls.

The original fixed price contract with Kiewit/Flatiron General Partnership to build the bridge was for $2.398-billion, documents obtained by Integrity BC show.

However the total amount paid to the Kiewit/Flatiron General Partnership is now $2.821-billion, according to research by Integrity BC.

“That’s more than $400-million. And it could get higher,” Travis said.

He compared that to the total cost of the Fast Ferries, which cost $450 million for three ferries that weren’t designed to operate in B.C. waters. It was a major scandal for the previous NDP government.

Another example Travis used was the $514-million BC Place renovation cost, which was first estimated at $100 million, then publically budgeted at $365 million.

The crown corporation responsible for the bridge, T.I. Corp, said the overrun was because the scope of the project changed to include more construction on the Cape Horn Interchange, to move rail lines, and hydro lines.

“We asked for more work,” said spokesman Greg Johnson. “The Cape Horn interchange in Coquitlam was where we went from four overpasses to 15 overpasses. We called that the megaproject within the megaproject.”

He insisted that the final cost of the entire project – which is still under construction – would be its budgeted $3.3-billion.

But the NDP’s Harry Bains doesn’t buy that. He says the bridge continues to lose money at the rate of $80 million a year, and is not even paying down the debt taken on to build the bridge in the first place.

He says it’s a matter of time before taxpayers will be on the hook.

“The younger generations will be asked to pay more. We will not be able to pay for this bridge,” he said.

The B.C. government is now planning to spend $3.6 billion on a new bridge to replace the George Massey Tunnel. Bains said the real cost will likely be much more.