WINDSOR, ONT. -- A panel of judges of the Ontario Divisional Court has overturned an arbitrator’s decision that allowed the closure of Nemak’s Windsor plant.

The decision was issued on Oct. 6, related to the November 2019 arbitrator’s decision.

Unifor said Justice D.L. Corbett accepted the union’s argument that it had a contractual commitment that the work must be done in Windsor if it is to be done by Nemak anywhere. The court found that the arbitrator misused evidence about the 2015 negotiation to get a different and unreasonable result.

“This decision affirms that Nemak is not above the terms of the collective agreement,” said John D’Agnolo, Unifor Local 200 president. “Our members showed incredible resilience, courage, and tenacity throughout this dispute and we are now one step closer to a resolution.”

Unifor said the arbitrator cleared the way for the transfer of specialized General Motors work to Mexico causing the loss of approximately 200 jobs.

“Today is a great day for our members at Nemak who spent months waiting patiently for the court to rule on the future of their jobs at the Windsor Aluminum Plant,” said Jerry Dias, Unifor national president. “This is precisely the outcome our union and our members were fighting for and the ruling could not be any more clear—when you have a collective agreement with workers you have to live up to its terms.”

In late November 2019, arbitrator Norm Jesin ruled against Unifor’s grievance and awarded that Nemak’s plant closure could proceed despite strong job security language in the collective agreement. Nemak and Unifor agreed in 2015 that new work for General Motors would be placed in the Windsor plant and that Windsor would be the “sole source” for that work.

The union immediately launched a judicial review of the arbitrator’s decision which was heard before the Divisional Court in Toronto in February 2020.

In an emailed statement to CTV News Lucy Wildman, Nemak communications leader for U.S. and Canada, said the business is “confident” Jesin will stick with his original ruling.

“The Divisional Court has ordered the matter to be returned to Arbitrator Jesin for review. We are confident in the original conclusions of Mr. Jesin and are optimistic that he would come to the same conclusion,” Wildman said. “We note that the Divisional Court found it was reasonable and grounded in the language of the collective agreement for the Arbitrator to conclude that Nemak is not required to operate an uneconomic plant.”

Tuesday’s ruling sends the union’s grievance back to the arbitrator for a new decision in accordance with the court’s reasons. The full decision can be viewed here.