The roughly 100-year-old Jones Act requires goods shipped between American ports to travel on US -flagged ships with American crews.
The U.S. government has issued periodic Jones Act waivers following severe storms in the past, to allow the use of cheaper or more readily available foreign-flagged ships.
While shipping the aid to Puerto Rico is one challenge, the U.S. Homeland Security Department says that moving the aid from ports into towns and neighborhoods is a much larger problem.
The Trump administration waived the act after recent hurricanes Harvey and Irma, which battered Florida and Texas. That comes after he accused the San Juan mayor of poor leadership and being unable to get workers to help Puerto Rico recover. If a foreign vessel is ready and willing to deliver medical supplies to a storm-rattled city, it makes little sense to deny it entry to that city's ports, for the sake of protecting employment in America's merchant-marine industry.
The White House has authorized a waiver to loosen shipping rules regarding Puerto Rico that island officials say would be a significant help for recovery efforts from Hurricane Maria. The island relies heavily on ports.
Now, the former businessman has approved shipping supplies "immediately" for the victims of Hurricane Maria.
When CNN Breaking News tweeted about five former presidents expanding their hurricane relief works to include Puerto Rico and US Virgin Islands, Rihanna quote-tweeted it and applauded them for their support.
Trump's waiver is in response to Rosselló's request, according to the White House.
That's what happens when it comes to gasoline and other fuels, said Tom Kloza, chief oil analyst for Oil Price Information Service.
Sen. John McCain (R-Ariz.) on Tuesday called for the Department of Homeland Security to lift the Jones Act in order to assist the devastated island. The move is meant to boost the delivery of much-needed relief supplies after Hurricane Maria battered the USA territory last week. It also affects other necessities.