PARIS (AP) —French investigators have confirmed that a powerful explosion at a bakery in Paris that killed four people and injured dozens almost a year ago was caused by a gas pipe break, authorities said Monday.

The Jan. 12, 2019 blast devastated a street in north central Paris, damaged a dozen neighboring buildings and forced dozens of families to find temporary accommodation for months.

Paris prosecutor Remy Heitz said in a statement Monday that the gas pipe broke due to ground subsidence caused by a water leak several years before.

Judicial experts have found that Paris street maintenance services and a private company in charge of the work failed to properly address the subsidence in 2016.

Firefighters were on the scene to investigate a suspected gas leak at the bakery when the explosion occurred. Two firefighters died in the blast.