The detonation of a half million pounds of high explosives inside a building proposed for storage of military munitions proved the safety of the buildings, Hill Air Force Base officials say.

"We're 100 percent sure it was a successful test. We gathered the data we wanted, collected more data than we needed, and even found a few things we weren't expecting," Maj. Mike Dougherty said Tuesday.The Nov. 18, 1988, blast in the uninhabited western Utah desert was the largest non-nuclear explosion in the continental United States, Air Force officials said.

"I've seen the draft" of the report, said Dougherty, test project officer. "The final touches are being added, but it looks 100 percent positive."

The explosives were housed in one so-called Hayman Igloo, a precast concrete building supported with metal beams. The blast destroyed the main storage structure and caused some damage to a second. But three other buildings located up to 250 feet from the main building were "shaken but intact."

"We've found that we'll have to do some redesign work to the igloo," said Dougherty. "But the test data gave us the information we needed to do that."

The buildings are 12-feet tall and 26-feet wide. They are built in sections 20 feet in length, he said, so the storage structure "can be 20-feet or 40-feet long, or whatever length you want in multiples of 20."

The November blast left a crater about 200-feet in diameter on the desert floor. A 2-foot layer of dirt on the nearest test structure was blown off, but other munitions stored inside were undamaged, officials said.