Braskem mined rock salt under a Brazilian city for 40 years — the ground finally caved

Braskem, Brazil's largest petrochemical company, had extracted rock salt from underground caverns beneath Maceió, the capital of Alagoas state, since the 1970s. University researchers began warning about the risk of subsidence from the resulting cavities as early as the 1980s, and Federal University of Alagoas geologists kept documenting the risk into the 2010s.

In February 2018, cracks appeared in streets and buildings in the Pinheiro neighborhood after heavy rain; a March 2018 earthquake widened them further, and the ground itself began caving in. By March 2019 the city had declared a state of calamity, and in May a federal geological survey formally confirmed that Braskem's mining had caused the subsidence.

Around 14,000 properties across five neighborhoods — Bebedouro, Bom Parto, Farol, Mutange and Pinheiro — were condemned, and roughly 60,000 residents were forced to relocate. Ten bus lines were shut down and a light-rail project under construction was suspended.

Braskem signed a relocation and compensation agreement with authorities in December 2019 and has since paid more than 3.7 billion reais (about $775 million) to residents and businesses, on top of a further 1.7 billion reais ($356 million) settlement with the city itself for public infrastructure. Total compensation commitments have been reported above 12 billion reais. Residents and local activists say individual payouts have often fallen short of what displaced families actually lost.

Kept mining despite warnings from the 1980s; when the ground caved in 2018, compensation exceeded 12B reais ($2B+), but payouts often fell short.

Decades of rock-salt extraction left underground cavities that were never filled or stabilized as mining continued.

Academic warnings about subsidence risk, raised as early as the 1980s, did not change the pace or method of extraction.

The company kept mining for years after researchers had documented the danger, treating the warnings as an academic dispute rather than an operational risk.

By the time cracks appeared in 2018, the underlying cavities were already too far collapsed to prevent the evacuation of entire neighborhoods.

A geological risk flagged by outside researchers for thirty years doesn't stay a research question — eventually it becomes the operating decision, at a scale no compensation fund fully undoes.

Braskem continues operating in Brazil while still processing compensation claims years later. The case is now Brazil's largest corporate-caused urban displacement and a reference point in the country's mining and environmental-liability law.