Fire still smoldered Thursday at a 400-foot crater in the ruins of a rocket fuel plant destroyed by earthquake-force explosions that flattened an industrial park, leaving one person dead, one missing and injuring more than 250.

"This thing could have been much worse. . . . We may have a miracle on our hands here," Gov. Richard Bryan said late Wednesday after blasts shattered windows 10 miles away in Las Vegas and tweaked seismographs 200 miles away.The detonations destroyed or severely damaged 12 buildings at the site of the Pacific Engineering and Production Co. of Nevada plant and an adjoining marshmallow factory.

The blasts - at least three powerful concussions and a string of lesser explosions - peeled off roofs, upended cars and even rocked a jetliner in flight. More than 250 people were injured, four critically, most from flying glass.

The tattered body found in the ruins was identified today as Bruce Bernard Halker, 56, vice president of operations at Pacific Engineering. A search continued for another possible victim.

"We have a missing person but we're not sure what it is. Maybe the person just left and hasn't contacted anyone," said Clark County Deputy Fire Chief John Pappageorge.

Bryan said he was declaring the blast zone and its environs a state disaster area, and would seek federal disaster relief for this southern Nevada desert community of 54,000.

"All the windows are smashed in and the roofs are peeled back," the governor said. "In one shopping center, all the glass is blown out and the top part of the building caved in. The force had to be enormous."

This morning fire still smoldered at the ruined plant, said Pappageorge, but it was not threatening or causing firefighters any problems. The blasts left a crater 400 feet across.

"Right now there are no fumes that are emitting from the ruins that we're aware of," Pappageorge said on the CBS "This Morning" program. "The last measurement that was taken, the particles were measured at zero."

He said of the low death toll: "Unbelievable would be the word. As my first thoughts when I arrived out there was there would probably be several hundred. But it's remarkable there was only one."

The explosions also spewed a 5-square-mile plume of toxic smoke into the sky, but winds carried the cloud away from populated areas and it eventually dissipated. By nightfall, evacuated residents were back at home.

Pacific is one of two manufacturers of ammonium perchlorate, an oxidizer in fuel for the space shuttle's solid rocket boosters and the Minuteman and Titan missiles. The other is Kerr-McGee, also near Las Vegas.

The explosions and fire were caused by an equipment malfunction, said Pacific president Fred Gibson Jr. No monetary estimate of the damage was available.