VANCOUVER -- Kinder Morgan has come under fire from two Metro Vancouver mayors for failing to answer hundreds of questions about a proposed $5.4-billion pipeline expansion.

The mayors of Vancouver and Burnaby issued a news release Friday criticizing the company for only answering half of their questions during the final round of National Energy Board consultations on the Trans Mountain project.

Of the nearly 600 questions submitted by Vancouver, the company failed to adequately answer 291, and of the 688 questions submitted by Burnaby, the company didn't fully answer 315, they said.

"The city continues to find very significant gaps in the information that Kinder Morgan has provided for a project that puts our environment and our economy at risk," Vancouver Mayor Gregor Robertson said.

Trans Mountain spokeswoman Ali Hounsell said the company tried to thoroughly answer all the questions it could, but some were outside the scope of the NEB process.

The proposed expansion would triple the bitumen-carrying capacity of the pipeline that runs from Edmonton to Burnaby, B.C. Almost 1,000 kilometres of new pipe would be built near the pre-existing line.

Sadhu Johnston, Vancouver's deputy city manager, said the questions were "basic" and very much within the energy board's parameters.

"Emergency response is very, very squarely in scope," said Johnston in an interview.

He said it's "absolutely ridiculous" for the company to say questions dealing with the definition of "emergency" and the consequences or impacts of an earthquake are out of scope.

"It really builds further concern for us about Kinder Morgan's transparency and their willingness to give us the kind of information we need to review this proposal."

Other questions that received "inadequate" responses focused on the time it would take company first responders to get to an incident site, how contaminated groundwater is monitored and detected and the findings of emergency drills, he said.

Johnston said the city has asked for clarification on 291 questions and Kinder Morgan now has two weeks to revise the answers or provide more information.

Meantime, Burnaby Mayor Derek Corrigan said his city has significant questions that focus on the hundreds of ways the project could threaten Burnaby's safety and livability, and he blamed the NEB for not requiring Kinder Morgan to disclose more details.

"I don't believe the National Energy Board is protecting our interests or even acting in the public interest," he said in an interview.

"I don't blame Kinder Morgan ... What do you expect from them except to only do what they are required to do?"

A NEB spokesperson did not immediately respond to requests for comment.

Natural Resources Canada issued a statement that said the board was a "robust, independent regulatory body" that conducts a science and fact-based review process.

"We have been clear: no project will proceed unless it is safe for Canadians and safe for the environment," it said.

Hounsell said Kinder Morgan received 5,600 questions during this round of questioning and got about 1,200 motions back from interveners including Burnaby and Vancouver asking for further information.

"We'll be reviewing all the motions, looking at each answer that we provided or didn't provide, and get back to the interveners and the National Energy Board."

Hounsell said the topics of earthquakes, safety, emergency response and groundwater monitoring are all "in scope" as long as they relate to the proposed pipeline and terminal facilities.

But she said the wording of the questions matters, for example if they relate to the existing pipeline. Further, she said Kinder Morgan may have provided an answer but the cities may simply feel it's not "adequate."