HALIFAX - A judge in Halifax is expected to make a ruling today on plans for a lawsuit against the federal and Nova Scotia governments.

Justice John Murphy will give his decision on an application to certify a class action involving the former Sydney steel plant.

The lawsuit is being prepared on behalf of people who claim their health has 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.

Murphy issued a partial ruling last year saying he would only certify the matter as a class action once the proposed class had been narrowed.

At that point, the proposed class had included residents and property owners within a 5.6-kilometre radius of Victoria Road and Laurier Street.