Efforts to build a new professional basketball arena in Seattle face a hurdle Friday as a judge hears arguments in a lawsuit to slow or stop the deal.

The International Longshore and Warehouse Union is concerned that adding a third stadium to the area south of downtown would choke freight traffic. The union says the stadium deal violates state law because it effectively commits to a site for the arena before an environmental review has been done.

Lawyers for the city, King County and the investment group planning to build the arena say officials will decide whether to invest in the new arena only after the environmental review is completed.

A group including hedge fund manager Chris Hansen and Microsoft Chief Executive Steve Ballmer has reached a pending deal to buy the Sacramento Kings and plan to move the team to Seattle.