As a Colombian labour activist began an indefinite hunger strike today, the United Steelworkers (USW) is intensifying international condemnation of trade union repression by multinational steel producer Tenaris.

"This is another stain on the reputation of Tenaris, which already faces a complaint before the United Nations' International Labour Organization for its systematic attacks on the rights of workers in Colombia," said Ken Neumann, USW National Director.

Two activists with the Sintratucar union, representing workers at the TuboCaribe steel plant operated by Tenaris in Cartagena, Colombia, chained themselves to a fence at the plant today.

One of the activists, Sintratucar vice-president Jairo del Rio, also started a hunger strike to protest a crackdown on workers' rights by Tenaris over the last several months.

In a complaint filed with the International Labour Organization (ILO) earlier this month, Colombian workers denounced Tenaris's attacks on the right to freedom of association and collective bargaining.

The complaint cites Tenaris for refusing to engage in good-faith collective bargaining and for targeting dozens of labour activists with suspensions and other sanctions.

Sintratucar's president was targeted after creating a WhatsApp group to allow young, part-time contract workers to report on their working conditions, which exposed a lack of training and numerous safety concerns.

The complaint to the ILO follows a similar complaint filed last year at the Organization for Economic Cooperation and Development (OECD) against a Tenaris sister company – steel producer Ternium – for violations of union rights in Guatemala. Tenaris and Ternium are part of the Italian-Argentine multinational conglomerate Techint.

The USW, which represents Tenaris workers in Canada, has joined with global labour federation IndustriALL (representing more than 50 million workers worldwide) in calling on Tenaris, Ternium and Techint to respect labour rights and negotiate in good faith with workers in Colombia and Guatemala.

"Tenaris would never get away with violating the rights of our Canadian members, such as freedom of association and engaging in union activism, because it is against the law," Neumann said.

"It is shameful that Tenaris workers in Colombia are compelled to go on hunger strikes and chain themselves to their workplaces to fight for these same, fundamental rights," he said.

"We join our international allies in calling on Tenaris to immediately stop its anti-union behaviour and to negotiate in good faith with its workers in Colombia," Neumann said.