Lebanese security officials warned the prime minister and president last month that 2,750 tonnes of ammonium nitrate stored in Beirut's port could destroy the capital if it exploded, news reports said on Tuesday.
Two weeks later, the industrial chemicals went up in a massive explosion that obliterated most of the port and swaths of the capital, killing more than 200 people, injuring 6,000, and destroying 6,000 buildings.
The Reuters news agency reported that an investigation by the General Directorate of State Security on events leading up to the explosion included a reference to a private letter sent to President Michel Aoun and Prime Minister Hassan Diab on July 20.
A senior security official summed up the findings of a judicial investigation launched in January, which concluded the chemicals needed to be secured immediately.
"At the end of the investigation, Prosecutor General [Ghassan] Oweidat prepared a final report which was sent to the authorities," he said, referring to the letter sent to the prime minister and president by the General Directorate of State Security, which oversees port security.
"I warned them that this could destroy Beirut if it exploded," said the official, who was involved in writing the letter and declined to be named.
Reuters could not independently confirm his description of the letter. The presidency did not respond to requests for comment about the July 20 letter.
A representative for Diab, whose government resigned on Monday following the blast, said the prime minister received the letter on July 20 and it was sent to the Supreme Defence Council for advice within 48 hours. "The current cabinet received the file 14 days prior to the explosion and acted on it in a matter of days. Previous administrations had over six years and did nothing."
The prosecutor general did not respond to requests for comment.
'Do what is necessary'
The correspondence could fuel further criticism and public fury that the explosion is just the latest, if not most dramatic, example of the government negligence that has already pushed Lebanon to economic collapse.
As protests over the blast raged in Lebanon on Monday, Diab's government resigned, though it will remain as a caretaker administration until a new cabinet is formed.
The rebuilding of Beirut alone is expected to cost up to $15bn, in a country already effectively bankrupt with total banking system losses exceeding $100bn.
Aoun confirmed last week he had been informed about the material. He told reporters he had directed the secretary-general of the Supreme Defence Council, an umbrella group of security and military agencies chaired by the president, to "do what is necessary".
"[The state security service] said it is dangerous. I am not responsible! I don't know where it was put and I didn't know how dangerous it was. I have no authority to deal with the port directly. There is a hierarchy and all those who knew should have known their duties to do the necessary," Aoun said.'No decision' made
Many questions remain over why the shipment of ammonium nitrate docked in Beirut in late 2013. Even more baffling is why such a huge stash of dangerous material, used in bombs and fertilisers, was allowed to remain there for so long.
The letter sent to Lebanon's president and prime minister followed a string of memos and letters sent to the country's courts over the previous six years by port, customs and security officials, repeatedly urging judges to order the removal of the ammonium nitrate from its position so close to the city centre.
The General Directorate of State Security's report seen by Reuters said many requests had been submitted, without giving an exact number. It said the port's manifest department sent several written requests to the customs directorate up until 2016 asking them to call on a judge to order the material be re-exported immediately.
"But until now, no decision has been issued over this matter," the General Directorate of State Security report said.