Still reeling from last month's court ruling that the environmental study is not flawed, the Longshoremen's Union will appeal.
It was a big victory for investor Chris Hansen. The environmental challenge against his plan to build an arena in Seattle's SoDo neighborhood was thrown out of court.
There is also an economic review, funded by Hansen.
The Port of Seattle says the scope of the economic review is too narrow.
"In short, the study is a sham," said Seattle Mayoral Candidate, Peter Steinbrueck.
At a news briefing on Tuesday, aside the Longshoremen's Union, Steinbrueck slammed the study.
"It's being fast tracked and it doesn't comprehensively examine the true economic costs," he said.
Critics want to see the economic impact of the arena to Port-related businesses and the SoDo manufacturing sector.
"The rents will skyrocket in that area because now we have entertainment and retail," said Peter Goldman, an attorney representing Longshoremen.
The economic study is being done by ProForma Advisors of Los Angeles. Critics say ProForma focuses on resorts and theme parks. They question the consultant's expertise on maritime and industrial business.
"There are troubling signs here that someone selected this consultant or in manipulating the scope of the study so it gives them the answers they want," said Goldman.
"The original scope of that report was determined by the City Council," said Seattle Mayor Mike McGinn.
McGinn says he'll broaden the study.
"We're going to work with the consultant to see how we can expand the scope," he said.
The report is supposed to be completed by the end of April.