A Seattle tour company is now facing a formal complaint from state regulators in the wake of the fatal crash that killed five people last week. The boats in question are similar to this one pictured.

According to the Washington Utilities and Transportation Commission (WUTC),  one of the vehicles operated by Ride The Ducks of Seattle was done so in an "unsafe manner."

Duck 6, the vehicle in question, reportedly contained a defective axle, and officials are trying to determine if the company was aware of a 2013 notification that there could be issues with the part.

According to the Commission, the vehicles in question that could contain the defective axle are called "stretch" Ducks, or longer versions of the old repurposed military vehicles.  Seattle officials say they will need to be inspected to ensure they are safe, and other city officials have called for a review as to whether the vehicles can operate safely on Seattle's Aurora Bridge, where the collision took place.

Ducks are military amphibious vehicles, which date back to World War II. They were used to transport troops ashore from larger troop ships, and were used in various forms for many years.  Ride The Ducks Seattle repurposed and refurbished the military surplus vehicles and turned them into amusement-tourist rides.

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