A proposed sports arena is the subject of a lawsuit, as a union representing about 3,000 longshoremen says it would put freight movement to the Port of Seattle — and their jobs — in jeopardy.

The longshoremen’s union  is suing the city and county over the plans to build a $490 million sports arena with $200 million in public bonds near Port of Seattle shipping terminals. According to the lawsuit, city and county officials approved an agreement with an investor to build the arena in the industrial Sodo neighborhood without completing a state law-required environmental review or evaluating alternate sites.

“Industrial lands need to be protected for the region and the future of the city. We don’t need more traffic. We don’t need more congestion,” said union member Max Vekich.

Pete Holmes, city attorney, said last week that the agreement reached with investor Chris Hansen does not preordain the Sodo site for the arena.