Why US-Iran war over Hormuz is threatening the Gulf’s waters

The United States-Iran war is increasingly being fought at sea, with both sides targeting oil tankers and other vessels in and around the Strait of Hormuz.

On September 8, the US struck five Iranian oil tankers, provoking an Iranian attack on Jordan’s Al-Azraq airbase.

Just three days earlier, the US also hit three other Iranian tankers. Those strikes came after Iran launched ballistic missiles towards a US aircraft carrier and a navy destroyer near the Strait, according to US Central Command. Iran too subsequently said it had targeted three oil tankers travelling through what it called an “unauthorised route” in the Strait, as well as three US-linked vessels elsewhere.

The tit-for-tat attacks have turned Hormuz into a potential environmental tinderbox. With tankers carrying millions of barrels of crude and petroleum products passing through or waiting around the waterway, a successful strike could trigger a fire, a sinking – or a major oil spill.

As of September 7, MarineTraffic data shows 42 tankers waiting to transit the Strait of Hormuz, while hundreds of other vessels are waiting or moving slowly in the wider Gulf of Oman and Gulf region. Of those tankers, 18 are carrying oil.

While it is not known exactly how much — if any — crude they were carrying, these vessels have an estimated combined capacity to carry 1.76 million cubic metres of oil and petroleum products – cargo that could be at risk if attacks on commercial shipping continue.

That — 1.76 million cubic metres of crude oil — is roughly 11.1 million barrels of oil, and is equivalent to about 11 percent of the world’s daily oil demand.

It is also enough oil to fill roughly 714 Olympic-sized swimming pools.