Two men have died after a mooring line snapped on a Taiwanese bulker in the US.

KOIN reported that the accident occurred alongside the 32,700-dwt Ansac Splendor (built 2005) at the port of Longview on Thursday.

Port officials said the recoil killed ILWU member Byron Jacobs, 34, at the scene.

The vessel's chief mate Pingshan Li, 41, died later in hospital.

"This is a tragic day on the waterfront," ILWU Local 21 president Jake Ford said.

"Byron was an active member of the union, loved his work and will be incredibly missed."

Another docker and a security guard were also injured.

The bulker is operated by Sincere Industrial of Taipei.