The unions representing Port of Seattle workers have made good on their threat to sue the city and King County over the proposed arena in SoDo.
Attorneys representing about 4,000 union port workers filed the suit in superior court on Thursday.
"We're blowing the whistle now because the foul has just been committed," says Attorney Peter Goldman. "We're not going to wait to the end of the game to start calling fouls."
The Superior Court lawsuit contends that Seattle and King County, working with investor Chris Hansen, have approved an agreement to build the arena in an industrial area south of downtown without first completing a required environmental review.
The King County Council and the Seattle City Council gave their final approval on Monday to an agreement to build a $490 million basketball and hockey arena in the city, despite the threat of the lawsuit from longshore workers.
Local 19 of the International Longshore and Warehouse Union contends that adding a third sports arena in the area will create more traffic congestion that will imperil "great working class jobs." The unions also claim the city and county failed to look at any alternative sites to the property south of Safeco Field.
Seattle City Attorney Pete Holmes has said the agreement does not bind the city into building the arena at any particular site, and says the agreement calls for a full environmental review as demanded by state law, as well as an analysis of effects on traffic and port operations.
The Associated Press contributed to this report.