By Daina Beth Solomon
MEXICO CITY (Reuters) - The biggest U.S. labor federation on Tuesday asked the U.S. government to open a complaint at a Saint-Gobain glass plant in Mexico, the latest in a series of petitions alleging worker rights violations in Mexico under a regional trade pact.
If U.S. labor officials accept the case, it would mark the sixth labor complaint under the 2020 United States-Mexico-Canada Agreement (USMCA), which aims to improve workplace conditions in Mexico and narrow the wage gap with the United States.
The U.S. Department of Labor declined to comment and French manufacturer Saint-Gobain did not immediately respond.
The AFL-CIO was joined by another major U.S. union, the United Steelworkers, in the request, alleging Saint-Gobain in the central state of Morelos unfairly supported its long-time union over a new, independent rival.
That group, the Independent Union of Free and Democratic Workers of Saint Gobain Mexico, also signed the petition. It will go up against the Confederation of Workers and Campesinos (CTC), which has held the contract since 1996, in an election Wednesday and Thursday.
Joaquin Guzman, a founder of the new union, said he hoped U.S. scrutiny could help end what he described as company favoritism towards the CTC at the plant of some 1,800 unionized employees that sends glass to carmakers including Volkswagen, Ford and Tesla.
"There isn't an even playing field," he said.
The petition alleges CTC representatives threatened a leader of the new union and halted work on production lines to pressure workers to support the CTC.
The CTC denied threatening a union member and said it has followed legal guidelines.
"Workers ... will make their decision with their vote," CTC spokesman Francisco Baron Hernandez said in a statement.
($1 = 20.3671 Mexican pesos)
(Reporting by Daina Beth Solomon; editing by Richard Pullin)