The Beirut explosion that killed at least 135 people and injured thousands appears to have been sparked by a warehouse fire, according to a new report

A fire at one port warehouse in the Lebanese capital Tuesday spread to a neighboring building, Warehouse 12, where 2,700 tons of highly volatile ammonium nitrate had been stored for years, igniting the massive blast, a source familiar with the initial investigation into the disaster told Reuters.

Another source told the news service that an inspection team warned six months ago that the combustible cargo could “blow up all of Beirut” if it were not removed after six years stashed in the warehouse.

“It is negligence,” the source said. “Nothing was done.”

The shipment of ammonium nitrate was confiscated in 2014 from a ship abandoned by a Russian businessman.

Beirut port General Manager Hassan Koraytem told reporters Wednesday that the material was put in the warehouse under court order after the shipowner went bankrupt.

Koraytem said he knew the material could be dangerous, but “not to this degree.”

With Post wires