The first fatal accident aboard a deep-sea tourist submersible is certain to raise calls for additional safety regulations, but industry experts say any new measures may be impossible to enforce given the international nature of the business.

Moreover, they say the tragedy of the Titan submersible that imploded during its expedition to the wreckage of the Titanic was an outlier, given that the maker of the vessel opted against certifying the vessel, defying industry convention.

All five people aboard the Titan, made by OceanGate of Everett, Washington, were killed in an incident that launched a multinational search mission and captured the world's attention.