By Dr. Mark J. Valencia, Special to the AJOT

On 4 January Iran detained the South Korean chemical tanker Hankuk Chemi for allegedly ‘repeatedly’ violating its environmental regulations and polluting its waters. The detention sparked outrage and fear of another crisis with Iran. Indeed, some linked the incident to the broader geopolitical quarrel involving U.S. sanctions on Iran for its pursuit of nuclear weapons. They implied that Iran seized the ship to use as a bargaining chip in negotiations to release some $7 billion of Iran’s money frozen in South Korean banks because of US sanctions.

The U.S. said, “The regime continues to threaten navigational rights and freedoms in the Persian Gulf as part of a clear attempt to extort the international community into relieving the pressure of sanctions.” South Korea demanded the tanker’s release, initiated legal action to that end and deployed a destroyer with its elite anti-piracy unit to the area. Even though Iran’s action may be politically motivated, it may be legally justified. It is important to sort out the issues involved and not jump to conclusions and overreact.

Unraveling the actions

This is certainly not the first time Iran has harassed or detained vessels passing through its claimed waters and it won’t be the last. However, it is different from the more dangerous disputes and incidents involving passage of US warships through the Strait of Hormuz. These incidents have occurred repeatedly and there are good legal arguments on both sides for their opposing positions regarding the conditions for passage of warships through the Strait.

But this case did not involve the question of innocent or transit passage of warships – or even alleged fuel smuggling which is the most common reason for Iran’s detention of tankers. Neither was it an alleged ‘hit and run’ as in the case of the British-flagged tanker Stena Impero whose detention did appear to be a tit-for tat political move. Nor was it state piracy as some have alleged: By internationally accepted definition piracy is an act committed for private ends by a private ship in waters beyond the jurisdiction of any coastal state.

The speculation that the detention is linked to broader issues is based on circumstantial evidence like the timing of the seizure of a South Korean -flagged vessel only days before a planned visit by South Korea’s Vice Foreign Minister Choi Jong-kun to Tehran. He headed a delegation to negotiate with his counterpart Iran’s Deputy Foreign Minister Abbas Araghchi for release of the funds.

Iran has been angered by the denial of its request by South Korea in consultation with the U.S. that the frozen funds be used to purchase COVID-19 vaccine and related medical equipment. Obviously, the tanker issue came up in the talks but Iran insisted that the two issues are separate, that the tanker was seized because it was leaking and that South Korea must await the outcome of the judicial investigation and proceedings. Choi demanded to see the evidence. But again, his counterpart deferred to the judicial investigation.

Iranian Position

Iran’s position is that the detention of the Hankuk Chemi was a routine response to a violation of Iran’s environmental laws that in general conform to international law. Even if the two issues are linked – and it is hard to imagine that they are not – at least in atmospherics – Iran does have the general right to enforce the law in waters under its jurisdiction. Iran is one of the few countries that has not ratified UNCLOS but it has signaled its general support by signing it. If UNCLOS is a guide, the applicable law depends on the regime governing the waters where the incident occurred. The questions then become what is the evidence of the pollution, where did the violation occur, where was the vessel arrested, and did it involve legal ‘hot pursuit’?

To determine the regime governing the waters where the incident likely occurred requires an understanding of the different interpretations of international law regarding Iran’s maritime claims in the area. Iran has drawn straight baselines along its coasts and claims a 12 nautical mile (nm) territorial sea, a 24 nm contiguous zone and a 200 nm Exclusive Economic Zone (EEZ) from these baselines extending to the boundaries between it and opposite countries. It also claims three islands just west of the Strait of Hormuz and territorial seas, contiguous zones and EEZs around them encompassing much of the navigable waters and the designated sea-lanes in that area… So, it is likely that the tanker passed through Iranian-claimed waters on its route from Saudi Arabia’s Jubail to the UAE’s Fujairah.

But some of Iran’s claims are disputed. The US (a non-party to UNCLOS) and presumably South Korea (which is a party) do not recognize the legitimacy of its claimed baselines along its mainland coast and thus the full extent of Iran’s claimed territorial sea in the Gulf. Moreover, they may not recognize Iran’s claim to the disputed islands west of the Strait and thus Iran’s territorial waters claimed from them.

UNCLOS and Freedom of Navigation

Although the US is not a party to UNCLOS, it insists that its provisions on freedom of navigation, including transit passage through such straits, are customary international law. More specifically, it states that ‘it is generally agreed that transit passage is a right of all states under international law’. That is certainly debatable. Many developing countries argue that the Convention was negotiated as a package trading off provisions regarding preferential access and sharing of seabed resources beyond national jurisdiction for liberal freedom of navigation, transit passage and archipelagic sea-lane passage for maritime powers. In particular, in the negotiations leading to the Convention, the US agreed to a 12 nm territorial sea in exchange for the transit passage regime.

UNCLOS allows the coastal state to adopt laws for the prevention, reduction and control of pollution and vessels in innocent passage or transit passage must comply with them. But transit passage cannot be impeded, hampered or suspended while innocent passage is more conditional. There was no such ‘transit passage regime’ before it was stipulated and elaborated in the Convention. The pre-existing regime was one of innocent passage in territorial seas and Iran apparently maintains that is the regime in its territorial sea-not transit passage.

The coastal state can restrict willful and serious vessel-source pollution within its territorial sea and EEZ. But direct enforcement is conditional on the location of the violation. If the pollution occurred in the territorial sea which is likely in this case it can do so. But if it occurred beyond the territorial sea, the coastal state can only enforce its environmental jurisdiction if the discharge causes or threatens major damage. That does not seem to be the case here.

Iran apparently exercised its right of hot pursuit. To do so legally, it must have had good reason to believe the ship had violated its laws. Moreover, the pursuit must have started when the violator was in its territorial sea or EEZ, and continued uninterrupted beyond the territorial sea. Also, the pursuit should have ended if and when the vessel entered the territorial sea of another state—in this case UAE or Oman. Again, this is why we need to know where the alleged violation and subsequent arrest occurred. Arrested vessels and crew must be released upon the posting of reasonable bond. It is not clear if such bond has been specified and posted.

The point is that this situation presents a very convoluted political and legal conundrum that needs to be sorted out by the two parties concerned. Speculation in the absence of facts and evidence, jumping to conclusions and overreaction are unwarranted.

This piece first appeared in Asia Times.

Editor’s Note: Dr. Valencia is an internationally recognized expert on Law of the Sea and Adjunct Senior Scholar National Institute for South China Sea Studies, Haikou, China.