The Beirut Port Explosion: Analysis of Potential Causes

By Evan Kohlmann

In the hours and days following the massive August 4th explosion at the port in central Beirut that caused over 200 deaths and inflicted billions of dollars in economic damage, there have been persistent questions regarding the cause of the twin blasts. The three most plausible immediate scenarios that emerged were: 1.) An airstrike (most likely by Israel) targeting Lebanese Hezbollah and/or Iranian assets in Beirut; 2.) An explosion in a hidden Hezbollah arms cache (whether through an airstrike or other cause) secreted at the port; and, 3.) A purely accidental explosion due to human negligence with no connection to military weapons or international terrorism.

Creator: Hussein Malla | Credit: AP

An Israeli Airstrike?

• The theory of Israeli involvement in the Beirut Port explosion was largely predicated on the heightened tensions between Israel and Hezbollah following a recent Israeli missile strike near Damascus International Airport. While there has been talk of a potential outbreak of hostilities between Israel and Hezbollah for months, tensions peaked in the wake of the July 20 missile strike that killed a Hezbollah operative, Ali Kamel Mohsen. 

• Though the death of Mohsen does not appear to have been deliberate, his killing was seen as a violation of the unstated status quo between Israel and Hezbollah and thus Hezbollah was widely expected to retaliate. At least one reported skirmish subsequently took place on the Israeli-Lebanese border (although this was officially denied by Hezbollah). Israel also reportedly sent a letter to Hezbollah through third parties warning the group not to attempt to retaliate.

• In the 36 hour period leading up to the Beirut explosion, as many as 22 or more Israeli reconnaissance drones and manned aircraft were reported by the Lebanese military to have been circling Beirut and over various areas of southern Lebanon.

• Nonetheless, there has been no evidence of any Israeli air strike or missile strike that has been publicly recovered or identified in the wake of the incident. Images being spread on social media that appear to show Israeli aircraft flying over the major explosion as it occurred or an Israeli missile gliding along a Beirut street towards the port have all been debunked as false. Neither Hezbollah nor Iran have seriously claimed that Israel carried out an airstrike, even though such a claim would likely be in their interests given the devastating outcome. While there was a significant level of activity by the Israeli Air Force in Lebanese airspace around the time of the blasts, this level of activity has been heightened since July 20 and there was no obvious increase specific to the day of August 4.

• In a published “Fact Check”, Reuters has shot down rumors of Israeli involvement, noting “Israeli Prime Minister Benjamin Netanyahu did not claim that the explosion in Beirut was due to an Israeli drone attack. Israeli officials have said Israel had nothing to do with the incident.”

An Explosion in a Hezbollah Arms Cache?

• Lebanese Hezbollah is known to have been working with its allies Iran and Syria for years in attempts to import sophisticated surface-to-surface rockets and other longer range weapons to threaten Israel. In turn, Israel has repeatedly targeted these stockpiles as they are transported from Iran to Lebanon (what is suspected to have happened with regards to the July 20 attack near Damascus International Airport). Similarly, there have been media reports over the past two years claiming that Beirut’s Rafic Hariri International Airport is also being used as “a smuggling point for Hezbollah.” Hezbollah must store its weapons stockpiles in camouflaged locations that are unlikely to be targeted by the Israeli military–for reasons that include the potential for undesirable collateral damage.

• Iranian rockets and missiles are not particularly known for their high quality, sophistication, or stability–and even without Israeli missile strikes to worry about, transporting and storing them is an inherently dangerous risk. This causal theory suggests that–whether due to the purposeful intervention of the Israeli military or simply the result of an accidental ignition–a Hezbollah weapons cache hidden in (or under) the port suddenly exploded on August 4.

• In a published “Fact Check”, Reuters has shot down claims that Israeli Prime Minister Benjamin Netanyahu previously identified the Beirut Port as a suspected Hezbollah missile site: “The posts all reference a speech made by Netanyahu at the U.N. General Assembly in 2018, in which he used a map to point to three Beirut locations close to the international airport where he said there were missile sites belonging to the armed, Iranian-backed Shi’ite group Hezbollah… The areas that Netanyahu points to during his speech are around Beirut’s Rafic Hariri International Airport, which is at least 5 miles (8 km) south of the blast site.”

• Hezbollah leader Hassan Nasrallah has strongly denied any involvement in the Beirut Port explosion and has demanded an objective investigation to establish the causes. In a speech broadcast by Hezbollah’s official Al-Manar TV, Nasrallah vowed, “I declare and confirm categorically that there is nothing of ours at the port, no weapons stores, no rockets, no guns, no bombs, no bullets, no nitrates–neither currently, nor in the past, nor in the future and the ongoing investigation will prove it.” He added, “We don’t run the port and we don’t know what’s in the harbor. Hezbollah is responsible for the real resistance, Hezbollah is knowledgeable about the Haifa Port in Occupied Palestine and not the Beirut Port.”

• The Lebanese military has likewise issued statements “categorically denying… news reports alleging that there are tunnels under the blast site at the [Beirut] port belonging to” Lebanese Hezbollah–and also rejecting media reports suggesting that Hezbollah fighters were deployed to the Beirut Port in the wake of the explosion to recover or hide potential evidence.

An Accidental Explosion Due to Negligence?

• The theory of negligence by government and port officials in the twin blasts is predicated on a shipment of 2750 metric tons of ammonium nitrate that first arrived in Beirut in 2013 on a Russian-owned transport ship named the MV Rhosus. The Rhosus was reportedly destined for Mozambique, but was forced to halt in Beirut when the owner declared bankruptcy.

• As described by Reuters, ammonium nitrate is “an industrial chemical commonly used in fertilisers and as an explosive for quarrying and mining. It is considered relatively safe if uncontaminated and stored properly. But it is extremely dangerous if contaminated, mixed with fuel or stored unsafely. A large quantity of ammonium nitrate exposed to intense heat can explode. Storing the chemical near large fuel tanks, in bulk and in a poorly ventilated facility could cause a massive blast. The larger the quantity, the greater the risk it will detonate.”

• Lebanese Information Minister Manal Abdel Samad Najd has stated there are papers and documents dating back to 2014 proving the existence of the “material” confiscated by Lebanese authorities from the MV Rhosus and stored at the Beirut Port. A 2016 letter from the Lebanese Customs Chief to the case judge responsible for determining the fate of the Rhosus and its cargo warned, “Due to the extreme danger posed by this stored items in unsuitable climate conditions, we reiterate our request to the Port Authorities to re-export the goods immediately to maintain the safety of the port and those working in it.” Journalists from CNN were able to reach the Mozambican explosives company who initially ordered the shipment of ammonium nitrate–and who responded, “We can confirm that yes, we did order it.”

• According to the New York Times and other news agencies, the U.S. embassy in Lebanon has recently dispatched a cable listing the Lebanese officials who were aware of the existence of the ammonium nitrate “which arrived in Beirut in 2013 and was unloaded into a port hangar the next year. The cable then says that an American security consultant hired by the U.S. military spotted the chemicals during a safety inspection… The cable said that the adviser ‘conveyed that he had conducted a port facility inspection on security measures during which he reported to port officials on the unsafe storage of the ammonium nitrate.’” 

• Reuters spoke with several explosives experts who commented on aspects of the Beirut blasts and what they could be indicative of. Stewart Walker from the School of Forensic, Environmental and Analytical Chemistry at Flinders University noted, “Video footage of the incident shows initial white-grey smoke followed by an explosion that released a large cloud of red-brown smoke and a large white mushroom cloud. These indicate that the gases released are white ammonium nitrate fumes, toxic, red/brown nitrous oxide and water.” He added, “If you make ammonium nitrate explosive, you shouldn’t get that brown plume. That tells me the oxygen balance was not correct – so it wasn’t mixed as an explosive… The Beirut blast looks like an accident, unless it was arson.”

Creator: Hussein Malla | Credit: AP

Based on the above information and analysis, it is a near certainty that the second larger explosion that took place at the Beirut Port was caused by the ignition of the 2750 metric tons of ammonium nitrate seized by Lebanese Customs officials from the MV Rhosus. It is also reasonably clear that the explosives did not originate from Hezbollah or Iran, they were not destined for Hezbollah or other Iranian assets, they were not hidden in a secret location at the port, and their existence was no mystery to Lebanese officials. As noted by Stewart Walker in his comments to Reuters, the slim remaining possibility of deliberate action here relates to the first smaller blast that eventually sparked the abandoned ammonium nitrate shipment. Yet, given the absence of any identifiable evidence of an Israeli missile strike or Hezbollah weapons being stored at the Beirut Port–and the strong denials from all the potential parties involved (including the Lebanese military)–it appears highly likely that the Beirut Port explosion was accidental and the result of regrettable human negligence.