The owner and manager of a cargo ship that rammed into Baltimores Francis Scott Key Bridge before the span collapsed last week filed a court petition Monday seeking to limit their legal liability for the deadly disaster.

The companies “limitation of liability” petition is a routine but important procedure for cases litigated under U.S. maritime law. A federal court in Maryland ultimately decides who is responsible — and how much they owe — for what could become one of the costliest catastrophes of its kind.

Singapore-based Grace Ocean Private Ltd. owns the Dali, the vessel that lost power before it slammed into the bridge early last Tuesday. Synergy Marine Pte Ltd., also based in Singapore, is the ships manager.

Their joint filing seeks to cap the companies liability at roughly US$43.6 million. It estimates that the vessel itself is valued at up to US$90 million and was owed over US$1.1 million in income from freight. The estimate also deducts two major expenses: at least US$28 million in repair costs and at least US$19.5 million in salvage costs.

The companies filed under a pre-Civil War provision of an 1851 maritime law that allows them to seek to limit their liability to the value of the vessels remains after a casualty. Its a mechanism that has been employed as a defense in many of the most notable maritime disasters, said James Mercante, a New York City-based attorney with over 30 years of experience in maritime law.

“This is the first step in the process,” Mercante said. “Now all claims must be filed in this proceeding.”

Cases like this typically take years to completely resolve, said Martin Davies, director of Tulane University Law Schools Maritime Law Center.

“Although it’s a humongous case with a very unusual set of circumstances, I don’t think it’s going to be that complicated in legal terms,” he said. “All aspects of the law are very clear here, so I think the thing that will take the time here is the facts. What exactly went wrong? What could have been done?”

A report from credit rating agency Morningstar DBRS predicts the bridge collapse could become the most expensive marine insured loss in history, surpassing the record of about US$1.5 billion held by the 2012 shipwreck of the Costa Concordia cruise ship off Italy. Morningstar DBRS estimates total insured losses for the Baltimore disaster could be US$2 billion to US$4 billion.

Eight people were working on the highway bridge — a 1.6-mile (2.6-kilometre) span over the Patapsco River — when it collapsed. Two were rescued. The bodies of two more were recovered. Four remain missing and are presumed dead.

The wreckage closed the Port of Baltimore, a major shipping port, potentially costing the area’s economy hundreds of millions of dollars in lost labor income alone over the next month.

Experts say the cost to rebuild the collapsed bridge could be at least US$400 million or as much as twice that, though much will depend on the new design.

The amount of money families can generally be awarded for wrongful death claims in maritime law cases is subject to several factors, including how much money the person would have likely provided in financial support to their family if they had not died.

Generally, wrongful death damages may also include things such as funeral expenses and the “loss of nurture,” which is essentially the monetary value assigned to whatever moral, spiritual or practical guidance the victim would have been able to provide to their children.