LAS VEGAS, Nevada USA — A fire at a hobby rocket engine plant burned into the night Monday, sending plumes of toxic smoke across the valley and forcing the evacuation of a square half-mile in eastern Las Vegas.

The blaze began with a pair of explosions about 12:20 p.m. at AeroTech Inc., near Sahara Avenue and Boulder Highway. Clark County firefighters, reinforced by colleagues from Las Vegas and North Las Vegas, quickly extinguished the blaze that sent flames 100 feet outside the company's front door and had employees running for their lives. But another blast hours later would prove impossible for firefighters to combat.

Eight people, including three firefighters, were hospitalized. Two people remained in critical condition late Monday with extensive burns.

Clark County Fire Department spokesman Steve La-Sky said the fire caused at least $12 million to $15 million in damage, and a wall at the AeroTech plant was at risk of collapsing near an adjacent apartment complex.

The incident has county officials questioning whether the company violated zoning laws by storing highly combustible materials in its facility, including 2,500 pounds of ammonium perchlorate -- a solid rocket fuel with up to three times the explosive energy of black powder.

"It was like a small earthquake that shook the whole building," Octavio Solorzano, who owns a car repair shop in the same structure as AeroTech, said of the first explosion.

Solorzano said the initial blast ripped a crack in the wall separating the two businesses. A rush of air was sucked into the crack and a second explosion rumbled the building 10 seconds later, he said.

By then, Solorzano and his employees were running from the building with the flames only steps behind them, he said. Solorzano saw three AeroTech employees running on fire and helped beat the flames off two of them, he said. One was severely burned all over his body and the other was scorched from the chest up, he said.

"They were burned big-time, and one was in complete shock," Solorzano said. "I knew them. They're our neighbors."

One person was in serious condition and two others were in fair condition Monday night. Three firefighters were hospitalized after suffering smoke inhalation while battling the three-alarm blaze, which seemingly was under control within minutes.

But at 3:30 p.m., a 55-gallon drum of magnesium ignited a flash fire in the building, La-Sky said. A trio of firefighters in the building were spraying the volatile materials with flame retardant and were able to escape without injury, he said.

The immediate area, including an apartment complex adjacent to the building that housed AeroTech, was evacuated. Around 5 p.m., fire officials widened the evacuation radius to about a half-mile because of the threat of more explosions and the toxic smoke.

Crews tried for several hours to get the blaze under control, but as the roof became unstable, firefighters retreated before it collapsed and set off more explosions.

By nightfall, about 70 firefighters on scene could only sit and watch as barrels of ammonium perchlorate and petroleum products from several automotive shops sent explosions, flames and thick, black smoke into the air. Individual rocket engines glowing purple and orange garnished the inferno as they streaked across the sky.

"This is essentially an unmanned fire," La-Sky said.

No cause was apparent Monday.

County zoning officials cast doubt Monday on whether the company had the proper permits to store ammonium perchlorate at the facility.

The building housing AeroTech, constructed in 1987, is zoned for light industrial activities. Storage of ammonium perchlorate and other volatile combustibles typically isn't allowed in light industrial areas unless the company holds a special permit, said Clark County Assistant Planning Manager Chuck Pulsipher.

"All I can say at this point is it's highly unlikely they had a permit," Pulsipher said.

The havoc such explosives can wreak in highly populated areas was evident Monday as residents were evacuated from their homes. The Red Cross opened an emergency shelter at Valley High School, and by 11 p.m. Monday between 75 and 200 people were expected to stay there. Jon Bastian of the Red Cross said the organization might put some evacuees in hotels.

As the residents waited to see whether they would be allowed to return to their homes, many expressed surprise and anger that a rocket motor plant was allowed to operate so close to their homes.

"I never knew there was a rocket plant, and I thought I knew that neighborhood real good," said Ed Dombrowski, 60, who has lived in the area for eight years. "That surprised the heck out of me. It's scary."

Dombrowski watched the explosion, which he described as a "little nuclear blast," from the roof of his home in the Maycliff Mobile Home Park, about a quarter-mile away. He later fled to the Red Cross shelter with his wife, Loretta, and their 87-year-old neighbor Margaret Puckett when smoke began to sting their eyes and throats and they lost power to their homes.

"I was afraid," Puckett said. "I didn't know if the whole thing was going to blow up."

Lon Dance, 41, unable to return to his residence at the Ponderosa Motel, was angered by the blaze.

"I want to know why this kind of plant was in a residential neighborhood," he said. "You can't have a plant like that in a residential neighborhood."

La-Sky said area residents would be able to return to their homes by this morning at the earliest.

According to the company's Web site, AeroTech was founded in Sacramento, Calif., in 1982. It moved to Las Vegas in 1985, and in 1987 it moved into its current facility at 1955 S. Palm St., Suite 15. The company manufactures and markets an advanced line of rocket kits, igniters and propellant formulations for hobbyists.

Copyright © 2001 , Las Vegas Review-Journal.