The worst of it is over, but there is still work to be done before it is safe to walk onto the property of an explosives-packed house that authorities burned to the ground.
Hazardous material officers plan to gently assess the danger of the charred property that was set ablaze Thursday morning in a controlled burn after nearby residents were evacuated. They also will analyze the leaves of trees for toxins.
Then they will scrape 2 to 6 inches of dirt off the half-acre lot to ensure there is no dangerous residue left.
A gardener stepped on residue from a volatile substance and set off an explosion last month. That accident led to the discovery of the home that prosecutors say contained the largest amount of certain homemade explosives ever found in a single U.S. location.
Authorities said the cluttered home was filled with so much dangerous material that they had to burn it to the ground to protect the neighborhood.
After more than 40 bomb experts and eight national laboratories analyzed the situation, they ignited the home remotely and then stood back and watched it disintegrate. Crews had built a 16-foot firewall and covered it with fire resistant gel to protect the closest house. Flames leapt up as high as the wall but the fire remained within the property.
Experts had tested some of the chemicals found inside the home and determined that if the fire reached 1,800 degrees, the toxins would neutralize within an hour and not cause any major explosions.
The toxins were neutralized within 20 minutes.
Flames engulfed the home quickly. Only a faint popping was heard. Officials said the noise was likely from ammunition and grenades. Weather conditions sent the plume up 2,500 feet and drifting slightly southeast, toward a closed down freeway and away from the most-populated areas.
After about two hours, San Diego County Sheriff Bill Gore declared the operation "essentially over." Authorities reopened the freeway, Interstate 15, about midday and residents who had been evacuated from the closest homes were expected to sleep in their own beds Thursday night.
"I guarantee if there's a similar situation in the United States, this is the incident that will be studied on how to handle it," said Gore, speaking at a news conference shortly after noon. "This is a textbook of how to do it. Something this scale, this magnitude, has not been done before."
Officials said they received no alarming reports of pollutants in the air. About 40 sensors were monitoring. Gore said the toxicity levels were probably lower during the fire than they are from traffic on the nearby freeway.
"I can't think of anything I would do differently or how this fire could have gone any better than it did," Gore said.
While the immediate safety threat had passed, Pat MacQueen, 76, and other residents were still haunted by the man who rented the house -- George Jakubec. How did he, as authorities say, amass so much explosive material and what did he plan to do with it?
"It was scary at first to think someone had been making bombs so close to me," said MacQueen as she watched the fire from about a block away.
Jakubec, an unemployed software consultant, 54, has pleaded not guilty to charges of making destructive devices and robbing three banks. He rented the house that authorities say had the kind of chemicals used by suicide bombers and insurgents in Iraq and Afghanistan.
The materials included Pentaerythritol tetranitrate, or PETN, which was used in the 2001 airliner shoe-bombing attempt as well as airplane cargo bombs discovered last month.
A coffee table was found cluttered with documents and strewn with detonators, prosecutors said.
In the backyard, bomb technicians found six mason jars with highly unstable Hexamethylene triperoxide diamine, or HMTD, which can explode if stepped on.
Christian Hoffman, special agent for the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives, said he felt excited watching the controlled-burn.
"It was kind of the equivalent of the Super Bowl for us," he said.
"Most people who came out here to watch were looking for big explosions. I think this was the perfect outcome," said Hoffman, gesturing toward the quiet, long plume of smoke drifting away.