Officials said poor handling of flammable materials was also a “contributing factor,” with several containers holding “dangerous goods and chemicals” reportedly exploding in the port’s yard. The Customs Administration of Iran later blamed a “stockpile of hazardous goods and chemical materials stored in the port area” for the disaster, without elaborating.

However, authorities cautioned that the exact cause was still under investigation. Notably, as per a report by Associated Press, the port had received a shipment of “sodium perchlorate rocket fuel” in March, according to the private security firm Ambrey — a chemical used in making missile propellants. While Iran has not confirmed this, the shipment had reportedly arrived from China, with the fuel intended to replenish Iran’s missile stocks after recent military operations, the report added.

Iranian President Masoud Pezeshkian has ordered an investigation into the causes of the incident. He wrote on X that the interior minister had been sent to the region to “examine the dimensions of the accident.”

Social media footage showed thick black and orange smoke billowing from the site before the explosion, with witnesses shouting warnings to evacuate: “Tell the gas (truck) to go! Tell him to go, it’s going to blow up! Oh God, this is blowing up! Everybody evacuate! Get back! Get back!”

The blast shattered windows several kilometres away, reportedly even being heard on Qeshm Island, about 26 kilometres south of the port. Footage shared by Iranian media and agencies like Reuters and Tasnim showed chaotic scenes of injured people lying on roads as overwhelmed hospitals struggled to treat hundreds of patients.

Relief workers battled fires well into the night, and port operations were suspended as evacuation and firefighting efforts continued. Port officials said several office buildings were severely damaged, and at least one building collapse was reported.

The explosion comes as Iran began a new round of nuclear talks with the United States in Oman. Iranian Foreign Minister Abbas Araghchi had warned just days earlier that the country’s “security services are on high alert given past instances of attempted sabotage and assassination operations designed to provoke a legitimate response.”

Iran’s biggest port

Shahid Rajaei port, part of Bandar Abbas, is a critical node for Iran’s trade, handling about 80 million tons (72.5 million metric tons) of cargo annually. It lies approximately 1,050 kilometers (652 miles) southeast of Tehran, near the Strait of Hormuz, the strategic waterway through which 20% of the world’s traded oil passes.

Bandar Abbas also holds crucial strategic and trade significance not just for Iran but also for regional connectivity projects like the International North South Transport Corridor (INSTC). The INSTC, initiated by Russia, India, and Iran, is a multi-modal route linking the Indian Ocean and Persian Gulf to the Caspian Sea via Iran, and onward to northern Europe through Russia. For India, Bandar Abbas is vital, serving as the gateway for goods moving from Mumbai by sea to Iran, then overland to the Caspian coast and beyond to Europe — providing an alternative trade route bypassing traditional chokepoints like the Suez Canal.