FORT LAUDERDALE, Fla. (AP) — A leak of refrigerated gas killed three people Tuesday on a cargo ship, including a supervisor investigating reports that workers were dizzy and two employees who tried to save him, authorities said Tuesday.

The victims were found unconscious in the hull of the ship, the Broward County Sheriff's Office said. The cause of death was chemical asphyxia due to inhaling argon gas, which had been leaking from a container the workers were loading.

Argon is colorless, odorless and nontoxic, but it can cause suffocation in a contained space.

The leak affected no one else, officials said. The shipping container is in a secured area of the Fort Lauderdale port.