HALIFAX - A judge says a case against the federal and Nova Scotia governments involving the former Sydney steel plant can proceed as a class-action lawsuit.

Nova Scotia Supreme Court Justice John Murphy says he's satisfied the plaintiffs' arguments meet the test to qualify for such a suit.

The lawsuit is being prepared on behalf of people who claim their health and properties have been harmed by living near the plant and the tar ponds.

The toxic tar ponds were the byproduct of roughly a century of steelmaking in Sydney and are now being remediated.

Ray Wagner, the plaintiffs' lawyer, says he is thrilled the case will go ahead after seven years of fighting to have it certified.

He says it could involve tens of thousands of people who allege that their land and health has been contaminated by lead, arsenic and other toxins.