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SAO PAULO (Reuters) - A group of international non-governmental organizations on Tuesday demanded that Brazilian miner Vale SA be excluded from the United Nations’ corporate responsibility pact, after a mining dam burst that killed an estimated 300 people.

A letter signed by more than 15 NGOs said that Vale failed to take proper safety measures at a tailings dam at its Corrego do Feijao iron ore mine in Minas Gerais state. The dam ruptured on Jan. 25, releasing a torrent of mud that buried workers and nearby communities.

The call for Vale to be expelled from the United Nations Global Compact, an agreement encouraging companies to adopt sustainable and socially responsible policies, is a symbolic step that signals growing international pressure on the company.

Vale declined to immediately comment, but has previously said the dam had all necessary safety certificates and was declared sound by an independent auditor in September.

The NGOs said the dam burst in the town of Brumadinho amounted to a “serious violation of human rights” and “grave environmental damage,” contravening the accord.

They said Vale should have done more to prevent the disaster after a similar incident in 2015 at Vale’s Samarco joint venture with BHP Group killed 19 people and devastated a major river, Brazil’s largest-ever environmental catastrophe.

“The Brumadinho disaster shows that favoring profit over safety has been Vale’s standard operating procedure,” the letter said.

Organizations that signed the letter include Greenpeace Brasil, MiningWatch Canada and the Global Justice Clinic of New York University.

Sao Paulo’s stock exchange on Tuesday also removed Vale from its ISE sustainability index.