The Coast Guard has grounded Hawaii Duck Tours pending the conclusion of an investigation into a flash fire that caused second-degree burns to an employee.

Firefighters said a gasoline explosion on a boat at the company’s Kakaako headquarters Tuesday morning sent a man to a hospital.

The vessel, one of the company’s two World War II-era amphibious craft, is scheduled for a follow-up inspection Friday to determine the cause of the accident, said Coast Guard Cmdr. Jason Neubauer, chief of prevention for Coast Guard Sector Honolulu.

When the company will be allowed to resume operations depends on the outcome of the investigation, Neubauer said.

He said a concern is a possible vapor hazard because the boats use unleaded gasoline, which may have been a factor in the flash fire on Tuesday.

Hawaii Duck Tours has two “duck boats,” the distinctive yellow amphibious craft that can travel on land and sea. The duck boats are over 60 years old, Neubauer said.

The company did not return a call for comment yesterday.

In Philadelphia, the National Transportation Safety is investigating a collision between a duck boat and a barge Wednesday that killed two people.

Investigators say the duck boat’s captain shut off the engine and dropped its anchor after smoke billowed from the vessel. The boat was stopped in the water for five to 10 minutes before the barge, being pushed by a tugboat, struck it. It capsized within seconds.

Among the issues to sort out: whether the tugboat crew heard distress calls that the duck boat crew says it made, and why an air horn on the smaller vessel apparently failed.

The NTSB interviewed the five crew members of the tugboat yesterday.
Ride the Ducks, the Norcross, Ga.-based company that owns the Philadelphia duck boat, said it was resuming operations in Atlanta, San Francisco and Branson, Mo., and expected to resume rides soon in Newport, Ky. Operations in Philadelphia remained closed.

A memorial service was also held yesterday for the two Hungarian students who died. Friends silently and solemnly dropped white roses into the Delaware River and clergy offered prayers in English and the Hungarian language of Magyar.

The Associated Press contributed to this story.