The US government has issued a second waiver of the Jones Act, this time to deliver a cargo of LNG to the hurricane-battered island of Puerto Rico.

US Homeland Security secretary Alejandro Mayorkas said that the waiver of the law was targeted and temporary in an effort to aid Puerto Rico as it continues to recover from Hurricane Fiona.

“In support of the Puerto Rican people as they continue to recover from Hurricane Fiona, I have approved a temporary and targeted Jones Act waiver to address the unique and urgent need for liquified natural gas in Puerto Rico,” he said in a statement.

“As with the previous waiver, the decision to approve was made in consultation with the Departments of Transportation and Energy to assess the justification for the waiver request and based on input from the Governor of Puerto Rico and others on the ground supporting recovery efforts.”

The Jones Act requires vessels built at a domestic shipyard, flying an American flag, owned by a US company and crewed by the country’s citizens to carry cargoes between two US ports.

Mayorkas said the law is vital to maintaining the strength of the US shipbuilding and shipping industries.

But the Homeland Security Department can issue exemptions for national security reasons when qualifying vessels are not available to meet the law’s requirements.

There are no Jones Act-qualified LNG carriers. Although six US-built vessels are operating in international markets, they are all owned by non-US companies and flying foreign flags, data from VesselsValue shows.

Puerto Rico governor Pedro Pierluisi said on Twitter that he requested the exemption to allow what he described as an LNG barge from the Dominican Republic. The vessel has not been identified, and it is unclear whether this means that the planned shipment involves a US LNG cargo that will be reexported from the Dominican Republic’s Andres LNG Terminal.

“We requested an expedited approval to ensure continued generation at the EcoElectrica plant,” he said, referring to the island’s gas-powered power facility.

The waiver is the second since Hurricane Fiona pummelled Puerto Rico in September. The first, involving a BP cargo on the 50,000-dwt GH Parks (built 2009), drew the ire of the American Maritime Partnership, a pro-Jones Act industry group.

“Granting of this waiver rewards calculated and predatory behaviour that undermines a dedicated American supply chain for Puerto Rico, and it is a harmful precedent that invites similar cynical stunts by foreign oil traders,” partnership president Ku’uhaku Park said at the time.

The group could not be immediately reached for comment on Monday.