Arguments are under way in a lawsuit aimed at slowing or stopping a deal to build a new professional basketball and hockey arena in Seattle.

King County Superior Court Judge Douglass North is expected to issue a ruling Friday afternoon on whether an agreement between the city of Seattle, King County and an investment group led by Chris Hansen violates state environmental law.

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 sued, saying an environmental review should have preceded any agreement.

Lawyers on the other side disagree. They say the agreement is preliminary and no environmental review was required beforehand.

Hansen has reached a pending deal to buy the NBA's Sacramento Kings and plans to move the team to Seattle.