Al Jazeera has investigated the passage of ammonium nitrate that exploded in the center of Beirut to the port. According to the media, the risks of the substance stored in the port warehouse for six years were well known to the authorities.

A cargo of ammonium nitrate arrived in the port of Beirut in September 2013 when a ship carrying it landed in Lebanon due to technical problems. The Russian authorities banned the Russian ship from leaving, and the ship was eventually abandoned. Ammonium nitrate was taken to storage.

The explosion destroyed the entire harbor.

Photo: AZIZ TAHER / Reuters

The explosion originated on a small promontory from a harbor in North Beirut. Beirut Ambassador Tarja Fernández describes the port, which was closed to the public, had warehouses “along the way”.

Image: AFP / Magazine image

In June 2014, the then Director of Lebanese Customs sent the first message to the Urgent Judge. In the message, he asked what to do with the huge amount of explosive substance. Over the course of three years, customs sent at least six messages proposing that the substance be exported, given to the Lebanese army, or sold to a privately owned Lebanese explosives company.

There was no answer. In a letter sent in 2016, Customs writes:

"As the storage of goods in unsuitable climatic conditions in a warehouse poses a serious risk, we renewed our request that the Navy be asked to remove these substances immediately for the safety of the port and its employees or to sell this quantity (to an explosive company)."

There was still no answer. In 2017, the new customs chief approached the judge, citing the danger posed by ammonium nitrate in the port, but he also received no response.

The force of the explosion and the pressure wave was enormous.

Photo: Bilal Jawich / ZUMA / MVPHOTOS

Nitrogen-containing ammonium nitrate is used in the manufacture of fertilizers and explosives in the construction industry, among others. The Taliban is also known for ammonium nitrate-based explosives. The most destructive factory explosion in Finnish history took place in January 1963, when ten tonnes of molten ammonium nitrate exploded. Ten people died.

In Finland, for example, the storage of a substance is strictly regulated. Tukes Chief Inspector Aki Ijäs considers the Beirut warehouse to be exceptionally large and in an inappropriate location.

- When you look at how central it has been. Residential and office buildings start right outside the warehouse, although there have been far too many to store in such a place.

In Finland, the substance may be stored in stacks of 100 tonnes, which must be such that the explosion cannot spread from one stack to another. There must be a distance of 350 meters to residential buildings.

On Tuesday, 2,750 tons of ammonium nitrate exploded, killing at least a hundred people and injuring more than 4,000. The entire port was destroyed, as was a significant part of the building stock in nearby neighborhoods.

The origin of the explosion is unknown, but it at least spread to an ammonium nitrate hall where more could have been stored. According to experts, the color of the explosion does not exactly match the pure ammonium nitrate.

Currently, Lebanese politicians consider the incident an accident. The country’s prime minister, Hassan Diab, has said everyone responsible for the blast will have to pay. According to President Michel Aoun, a mistake in the handling of ammonium nitrate is unacceptable and all those responsible for it will receive “the most severe punishment”.