The Toronto Port Authority has been given a thumbs up to go ahead with a controversial project.

An environmental assessment just released says there would be "no adverse significant effects on the environment" if the material being dug up to build a pedestrian tunnel is placed into the lake next to the island airport's main runway.

The lakefill project can now get started as soon as April.

The TPA says the lakefill will be a physical safety deterrent, preventing boats from getting too close to the runway. The authority has also said the project will reduce the volume of trucks hauling away excavated material from the pedestrian tunnel.

But critics have questioned the port authority's intentions.

"The port authority's plans for the waterfront are for the interest of the port authority not in the interest of the city," says councillor Adam Vaughan

He says those interests involve industrializing the waterfront.

"They would see an operation there that would rival Pearson," Vaughan says. "That's not good for the city."

Vaughan suspects the lakefill project is a way for the port authority to dump the excavated material. Brian Iler, an activist with the group Community Air, agrees.

"They're just looking for ways to save money," Iler says.

During public consultation meetings last year, local residents also accused the port authority of wanting to use the lakefill in the future to extend its main runway.

The port authority has denied that, saying their agreement with the City of Toronto and Transport Canada does not allow for runway extentions. They could extend a runway if all three parties agreed to it, but director of infrastructure, Ken Lundy, says they are not exploring that.

"That's not certainly part of what we're intending," Lundy insists.

Vaughan says he would not want to see an expansion of the island airport.

"Any expansion plans for jets or bigger airplanes would really hurt this city," Vaughan says.