Legitimate ship-to-ship (STS) oil transfers risk being caught up in a proposed crackdown on clandestine operations that seek to evade sanctions or high insurance costs, tanker owners have warned.

A group of nations wants stricter policing of STS rules to target a “dark” or “shadow fleet” of lightly regulated ships hauling sanctioned cargoes, but Intertanko, which represents independent tanker owners, warned that mainstream operators could also be affected.