Flames are no longer visible from a train propane tanker car that had been burning in Lincoln since Tuesday afternoon and thousands of residents evacuated because of the danger of explosion have been allowed back to their homes.
As of 4:15 a.m. Thursday, flames could no longer be seen above the rail car, likely meaning most residual propane vapor inside the tanker car has been burned off.
Fire suppression personnel were going to continue flowing a water and foam mixture into the tank for another two hours to make sure it is completely evacuated, said Lincoln Fire Dept. Battalion Chief Tolan Dworak.
At midnight, with just small flames rising from the tanker and most of the liquid propane in the 30,000-gallon car believed to have already burned off, fire officials reported the burn was controlled and they were confident the car was stable.
Lincoln residents who had been evacuated from within a one-mile radius "blast zone" were allowed to return home.
By that point, firefighters had already begun pumping the rail car full of water and aqueous foam in an attempt to force out residual liquid and propane vapors, said Lincoln Fire Chief Dave Whitt. The fire, which had gone out briefly around 8:30 p.m., was re-lit in order to burn off those residual vapors, Whitt said.
At about 11:30 p.m., Whitt said firefighters felt "pretty confident that the water is filling up the tank, pushing out the vapors. Basically we've got a nice propane fireplace type of thing."
It was a marked change in tone from several hours earlier, when fire officials were planning a delicate operation to drain liquid propane from the tank car. Officials had feared that building pressure in the car could lead to an explosion.
The "hot tap" procedure, for which specialists were brought in from Fort Worth, Texas, would have involved welding a valve to the car, drilling a hole and allowing the liquid to drain into a ditch, where it would be burned off, fire officials said.
Preparation for the procedure was underway at 8 p.m., when Whitt addressed media members saying that there could still be as much as 25,000 gallons of liquid propane in the rail car, and that there was still a potential for "catastrophic failure."
However, officials began to reassess the situation when personnel at the scene began noticing that flames coming from the rail car were becoming "lazy," and that the fire was extinguishing itself, Whitt said.
They tested the weight the car was putting on its springs, and ran a heat test, and became "99 percent sure" that the liquid propane had burned off, he said.
Officials halted the "hot tap" procedure and began pumping the foam and water mixture into the car at 200-300 gallons per minute, Whitt said at a 10 p.m. news conference.
They later lifted the evacuation order effective at midnight.
A few minutes before midnight, a police car and motorcycle blocking eastbound First Street at Joiner Parkway pulled away from the intersection with a blip of a siren, allowing a stream of residents in cars to return to their homes.
Nearly 5,000 homes were evacuated in the "blast zone" beginning Tuesday afternoon. Three shelters were set up in the city for evacuees.
Dawn Lindblom of the American Red Cross said that those shelters would remain open overnight and serve breakfast Thursday morning, in case people had already settled in for the night, but that many evacuees were returning home.
"It's a blessing to be able to go home," said Ruth Escobar, 33, leaving the shelter at First and Joiner with her two children. "He can't go to sleep in a place that he doesn't know," she said, indicating her nearly 2-year-old son, who had begun to cry in his stroller.
According to the City of Lincoln website, Lincoln schools will be closed the remainder of this week and anticipate opening on Monday. City Hall will be open Thursday for normal working hours, according to the website.
The cause of the fire that led to the evacuations and closure of some area businesses was still unclear. Whitt said that all signs pointed to an accidental spark, but that the cause remained unknown pending an investigation.
The fire, Whitt said, "has impacted a lot of people, it's impacted some businesses, it impacted Highway 65. But it could've been much worse."
Fire crews responded about 12:30 p.m. Tuesday to 911 emergency calls about flames shooting from the top of the full 30,000-gallon propane rail car parked on a spur off the Union Pacific main line. One person had been burned. That person has since been released from the hospital, Whitt said.
Quickly recognizing that the gas-fueled blaze would outpace his 24-man department, Whitt summoned help from agencies across the region, including the California Department of Forestry and Fire Protection.
Surveying the area, authorities determined that at least 170,000 - and as many as 500,000 gallons - of propane were in nearby rail cars, significantly increasing the risks.
Authorities evacuated neighborhoods within a mile radius of the fire, including the downtown commercial core, schools preparing for the first day of classes and the city's signature business, clay-products manufacturer Gladding, McBean. Three shelters were opened; nearly 300 residents used them overnight.
Firefighters fought to keep the pressure within the burning tanker at safe levels, training 5,000 gallons of cooling water a minute at the car through unmanned hoses.
But as the fire raged, concerns mounted that the tanker's integrity was deteriorating, increasing the possibility of a blast. Officials feared an outcome like the 1973 Kingman, Ariz., tragedy, in which 11 firefighters died fighting a propane fire at a railyard.
On Wednesday, with the threat of a catastrophic explosion as the rail car fire raged, Lincoln officials had embarked on the risky "hot tap" operation to divert propane from the flaming tanker into a dug-out pond, where it could be safely burned off.
That effort was led by a team of professionals from Fort Worth, flown in by chartered jet late Tuesday and known for their experience with such emergencies.
The hot-tap procedure that had been prepared has been used for decades. Perhaps most notably, it was used to help extinguish the Kuwaiti oil well fires in the early 1990s.
But the circumstances in Lincoln - including unbearable heat emanating from the fire and the presence of more propane nearby - made it an unusually dangerous operation, experts and officials agreed.
As such, about 100 firefighters and paramedics were staged outside the 2-mile-wide potential "blast zone" - covering nearly 5,000 evacuated homes - should anything go awry.
Though officials said the SRS hot tap operation was the best solution, their hesitation was clear: Twice during a morning press conference, Whitt said he was "fairly confident" it would work.
According to experts, the hot-tap process - minus fire - is used frequently to safely tap into a pressurized pipeline or vessel that can't be depressurized or shut off.
For example, it's used to create a pipeline for a new neighborhood off a natural gas main line, said Kyle Makofka, vice president of business development for the Canadian firm Red Flame Industries.
However, he said the situation in Lincoln was "substantially different," in part because of the fire and how it created its own pressure and temperature challenges.
He added that the propane's flammability increased blast risk: "You don't want to be in the area when that happens."
Others observing the blaze - including the company that owns the burning propane and the property - appeared to share that concern.
"We are 30 hours into this release. It is of great concern to us," said Eric Beatty, secretary and general counsel of Heritage Propane, said at the time. Heritage Propane uses the name Northern Energy at some of its propane-storage facilities, including this one.
A Heritage Propane crew had prepared to unload the propane, produced by British Petroleum, from the rail car when the fire ignited.
The facility is a terminal where propane gas, brought in by rail, is stored in bulk tanks before being trucked to retail outlets.
Hazardous materials crews from UP and the Federal Railroad Administration were on the scene to assist firefighters. The California Public Utilities Commission, which conducts hazmat inspections, also had representatives at the site.
In an email to The Bee, the PUC said an "early review of inspection reports reveal good practices on the part of the shipper, Heritage, but we will perform a more thorough review of Heritage's records."
The PUC said Heritage Propane employees also have received federally required training on safe handling of hazardous materials while loading and unloading, and participated this year in a federal seminar on federal hazmat handling regulations.
On Wednesday evening, Lincoln residents had waited anxiously for updates. At one shelter, volunteers tried to keep spirits up with a barbecue and ice cream. Representatives from insurance companies were on hand to counsel evacuees - and give out free dog food to pet owners.
"We're just ... getting as much information as we can, talking with friends, just waiting it out," said Linda Kaveney, who was there with her twin sister and 18-year-old daughter.
Earlier, officials had warned residents that a huge, dark cloud of smoke would develop once the pond was filled with burning propane. But even as the propane's flammability posed a threat to firefighters, it didn't pose one to the ozone.
"Propane in its nature is a clean-burning fuel ... and there are no toxins associated with (its) combustion," said Heather Kuklo of the Placer County Air Pollution Control District.
"That, in and of itself, is a real positive for this situation."