The investigation is focused on why nearly 3,000 tons of explosive ammonium nitrate was being stored at the city’s port. The ignition of the stockpile caused an explosion that tore through the capital, killing at least 180 people and wounding 6,000.
Thirty people are still missing after the August 4 blast.
Documents that surfaced after the explosion, the single most destructive in Lebanon’s history, showed that officials have known for years that 2,750 tons of ammonium nitrate were stored in a warehouse at the port and knew about the dangers.
Judge Fadi Sawwan questioned customs chief Badri Daher, who was detained days after the blast, for four-and-a-half hours in the presence of his two lawyers before issuing the arrest warrant, the National News Agency (NNA) said.
Mr Daher will remain in custody as the investigation continues.
The NNA said that after questioning Mr Daher, the judge headed to the scene of the explosion to survey the damage and will later return to question Hassan Koraytem, who was the top port official until the day of the blast.
Lebanese president Michel Aoun said the probe into the disaster is “very complex” and would not be finished quickly.
Mr Aoun said the probe is divided into three parts. The first aims to determine the circumstances surrounding the cargo, the second where it came from and who shipped it, and the third to find who was responsible for handling and securing it.
Mr Aoun said the American FBI and French investigators were helping because “they, more than us, have the capability and ability to find out the details of what got the ship here, what is the source and who owns it”.
A nine-member team of FBI investigators landed in Beirut on Sunday, according to a Lebanese aviation official, and were believed to have joined the investigation. French investigators have been active for days at the port.
