Confusion over stricter new liability guidelines under the Oil Pollution Act of 1990 could create troubled waters for cruise lines, petroleum companies and an array of other businesses that qualify as owners or operators of tankers, cargo ships and other large vessels visiting U.S. ports, according to a maritime law expert.

Jonathan Gutoff, an admiralty law professor at the Roger Williams University School of Law in Rhode Island, asserts many owner-operators are in the dark about the new standards or mistakenly believe that they’ll enjoy the same limited liability under a now-outdated interpretation of OPA.