The B.C. government as well as several Metro Vancouver municipalities and First Nations Bands had argued they needed more information about how the company planned to respond in the event of a spill.
But the company argued it didn't want to release the details for "personal, commercial and security reasons."
In a statement Trans Mountain said the plan is only intended for "first responders, local agencies and authorities involved in responding to an emergency...and it's not meant for public consumption."
The NEB ruled in favour of the company on Thursday, just one day before the deadline for information requests as part of the second round of hearings.
"In this instance, the board is satisfied that sufficient information has been filed from the existing EMP documents to meet the board’s requirements at this stage in the process," said the board in its decision
The company is seeking approval from the NEB to nearly triple the capacity of the existing pipeline. The $5.4 billion project would twin the existing pipeline that runs from Edmonton to Burnaby, B.C.
Green Party MLA Andrew Weaver was critical of the NEB decision not to require the release of more detailed plans.
"They don't even know what the emergency response plan is. It's simply unacceptable."
Without the details of the plans, the province should launch its own independent assessment of the project, he said.
"There is only one thing the province can do right now and that is to say, 'You know what, this is the line in the sand we drew... It is our right to see the emergency response plan. You have not given it to us. You have redacted out large sections.We will conduct our own independent assessment process now.'"
Wilderness Committee campaigner Eoin Madden was also concerned by the lack of information released by the company.
"Once again...we're finding out that critical information to keep us safe, information we need to keep our children safe, keep the atmosphere safe, is being withheld."
On Friday the City of Vancouver submitted nearly 600 questions to Kinder Morgan, many specifically aimed at emergency and spill response.
Hearings on the project are ongoing