SPOKANE, Wash. – A local model rocket expert said the type of metal pipe students at the University of Idaho were using while testing experimental rocket fuel is potentially dangerous.

Officials said four students had to be hospitalized when some of the fuel they were testing exploded. All of the details of the experiment were not exactly clear as of Friday afternoon but officials have said the students were using a galvanized metal pipe.

Bob Yanecek is the president of the Spokane Area Rocket Club. He has been flying model rockets for over 40 years. Some of the students from the University of Idaho’s Northwest Organization of Rocket Engineers went to a recent launch that Yanecek’s club put on.

"Very, very enthusiastic. I was incredibly impressed with their enthusiasm,” he explained.

Yanecek said the students were there just to chat.

School officials said the students were using eight to twelve inches of galvanized metal pipe in the test and that is what sticks out to Yanecek.

"The galvanized pipe thing is a definite red flag,” Yanecek said. "There's a reason terrorists use them for pipe bombs. Because galvanized metal pipe, if it does over pressurize, it can fracture into pieces."

Galvanized pipe is not the safest or wisest choice in the model rocket community, Yanecek explained. Then there's how the test came about. An empty parking lot isn't necessarily a bad idea. He said what is questionable is how close the students were to the rocket at the time.

"Every event, your safety distance is based on expecting this to happen. Or preparing. You don't expect it to happen, but you always prepare for it to happen," he said.

Yanecek said that if you follow the guidelines and play it safe, rocketry should not be dangerous.