Vale SA’s (VALE.N) dam breach has left at least 60 people dead and 292 missing in Brazil, leading the world’s biggest producer of iron ore to suspend dividends as it braces for the financial fallout of the catastrophe. The shares plunged the most on record and wiped out about US$18 billion in market value.

The collapse Friday of a tailings dam at the Feijao mine in the rural state of Minas Gerais is Vale’s second fatal disaster since 2015, when the Samarco mine spewed billions of gallons of waste. Mayor Avimar de Melo of the city of Brumadinho, which was partly leveled by the spill, is seeking millions in damages and blamed Vale’s “incompetence” for the incident. Brazil’s Prosecutor General Raquel Dodge said company executives may be held responsible.

“Given that this is the second dam burst linked to Vale, we would expect more stringent remediation requirements and tougher penalties,” Macquarie Capital Ltd. analysts including Grant Sporre wrote on Monday.

The company’s shares were down 23 per cent to 45.11 at 1:53 p.m. local time -- local markets were closed for a holiday on Friday. Vale’s US$2 billion in bonds due in 2026 have fallen to the lowest since 2016 at 102.79 cents on the dollar.

Iron ore futures in China surged to the highest in more than a year on concern that global supplies will be interrupted.

The disaster will be the first major test of Vale Chief Executive Officer Fabio Schvartsman, who took the job less than two years ago. His predecessor, Murilo Ferreira, was heavily criticized for the Samarco disaster that killed 19 people and polluted waterways in two states, and his seemingly lackluster response was later used against him by rivals eager to replace him.

On Sunday, Renan Calheiros, a candidate for Senate president, tweeted that Vale’s top management should resign. Vale declined to comment.

The disaster also comes less than a month after the inauguration of Brazil President Jair Bolsonaro and may upend his plans to ease environmental restrictions and boost mining production through reforms in Congress.

Vale’s board decided to halt dividends after an extraordinary meeting held on Jan. 27, according to a statement. At least five analysts have downgraded Vale’s American depositary receipts since the accident.

S&P Global Ratings put Vale’s bonds on CreditWatch on Friday, warning that it may be forced to shut some operations. Three judges have already frozen almost US$3 billion of the miner’s funds to ensure it will be able to compensate victims and pay for the clean-up. Vale has also agreed to set up committees to probe the disaster and support the victims.

Schvartsman said the latest disaster must spur the company to raise safety standards to a level “far superior to what we have today.” The Feijao project is one of its smaller operations, producing 7.8 million tons of ore in 2017, or about 2 per cent of total output.

Analysts at Macquarie estimated that the earnings hit would be limited because of the company’s balance sheet strength and robust cash generation.

“The company can cover the remediation cost with ease,” Macquarie said. “However, Vale’s equity re-rating story was in part a reputational one which has now been dealt a body blow.”