The US National Hurricane Center (NHC) said a potential tropical cyclone in the Caribbean was expected to rapidly intensify over the gulf’s warm waters and could become a major hurricane with winds of up to 185kph by Thursday.

The storm, which would be called Helene, could hit the US as a category 3 hurricane on the Saffir-Simpson wind scale, bringing the “risk of life-threatening storm surge and damaging hurricane-force winds” to the northeastern Gulf Coast and Florida Panhandle, according to the NHC.

Oil companies BP, Chevron, Equinor, and Shell, have begun evacuating offshore staff, and several have paused some production.

BP shut oil and gas output at its Na Kika and Thunder Horse platforms and curtailed output at two others, Argos and Atlantis. Employees are being removed from those four platforms and a fifth, called Mad Dog, it said.

Chevron said it has begun evacuating all personnel and shutting in production at its Blind Faith and Petronius offshore platforms.

Non-essential staff are being evacuated from Anchor, Big Foot, Jack/St Malo, and Tahiti. Production remains at normal levels at those platforms, it said.

Equinor said it was evacuating non-essential staff from its Titan platform. Production has not been affected, it said.

Occidental Petroleum said in a web post it would implement safety procedures “as appropriate” at its offshore operations. Talos Energy declined to comment on its storm preparations.

Shell said it had shut in production at its Stones platform, curtailed production at its Appomattox facility, and was pausing some drilling operations. Non-essential staff from Mars, Olympus and Ursa offshore facilities were being evacuated. Production at those three continued, Shell said.

“The system is expected to grow in size while it traverses the Gulf,” said NHC meteorologist Brad Reinhart.

Its “fast forward speed as it approaches the coast will likely result in farther inland penetration of gusty winds over parts of the southeastern US after landfall.”