Chantilly — If his children hadn’t insisted on looking at Christmas lights on their way home from dinner, Thuan Nguyen, his wife and their two sons might well have died in the Dec. 19, 2010, gas explosion and fire that demolished their Chantilly home.

The Brookfield family had eaten at a restaurant in Manassas and finished around 8 p.m. “We were planning to go straight home, but the children [ages 6 and 14] wanted to see the Christmas light show at Bull Run, on the way back,” said Nguyen. “We were in the car driving home from it when I got the phone call from my neighbor [about the explosion].”

Their house blew up around 8:45 p.m. and, said Nguyen, “When I got home, I could see only fire. If we didn’t go to the Christmas light show, we might have been home at the time of the explosion. It was a miracle.”

Some 60 firefighters from five stations — including two hazardous-materials units — rushed to the scene after receiving 911 calls from neighbors about a gas leak, an explosion and a fire. The two-story house at 4303 Lees Corner Road, near Pennsboro Drive, was completely destroyed; Fairfax County fire officials estimated the damage at $400,000.

Since then, the Nguyens have built a new home — all-electric — on the same site. And both Washington Gas and the Virginia State Corporation Commission’s (SCC) Division of Utility and Railroad Safety have completed investigations.

In its Nov. 30, 2011 report, the SCC concluded that the gas company committed numerous probable violations, both before and after the explosion, and that the exact cause of the explosion could not be determined. Last Wednesday, May 23, the SCC announced it has reached a settlement with Washington Gas regarding this incident.

According to the terms of the settlement, the gas company does not have to admit or deny violating any safety standards. But it had to pay a fine and must also make several safety improvements in Brookfield.

Washington Gas was ordered to pay a $154,800 penalty to the Commonwealth of Virginia, with another $219,700 due if the remedial actions detailed in the settlement order are not met. It has until Nov. 30 to replace all the copper service lines in the immediate neighborhood where the explosion occurred.

The company must also test and collect information on the copper service lines as they are replaced. Washington Gas will then use its findings to assess the integrity and enhance the safety of all its other remaining copper service lines in Virginia. It must also report the results to the SCC and take the appropriate actions necessary to remedy any potential problems.

In addition, Washington Gas has been directed to revise several of its own procedures, including those dealing with how it responds to emergencies. And by July 31, it must give all its field employees and contractors refresher training regarding the identification of abnormal operating conditions and how to report them to the company.

LAST THURSDAY evening, May 24, SCC and Washington Gas representatives attended a Brookfield Civic Association meeting and shared information with the residents about both the investigation and the settlement.

“We interviewed witnesses and homeowners and tested the underground facilities to determine a timeline of events,” said Shane Ayers, SCC safety program manager. “We also reviewed thousands of records. The investigation that ended Nov. 30, 2011 yielded 18 specific findings, plus nine probable violations committed by Washington Gas.”

Some involved SCC Pipeline Safety Standards, and others were violations of its own gas-company policies — or lack of a policy, he said. But Ayers said none involved how Washington Gas responded to the emergency.

The investigation couldn’t definitively pinpoint the source of the gas that led to the explosion because there was more than one, legitimate possibility:

• There was a corrosion leak on the copper service line leading to the house;

• A 2008 addition to the home was built over the gas service line – which violates the Pipeline Safety Code; and

• A customer fuel line inside the house on the second floor had never been capped and was open-ended.

Ayers said that, by June 15, Washington Gas will replace all service lines underneath structures “to prevent any reoccurrence of what happened.” He also noted that the company was actually ordered to pay a civil penalty of $374,500, but all but $154,800 was suspended and it “won’t pay the rest unless it doesn’t meet [the remediation] deadlines.”

“We’re doing everything we can to enhance public safety,” said Ayers. “And Washington Gas is taking this very seriously, as well.”

Steve Price, Washington Gas division head, Construction and Operations, said his company’s construction team would be happy to speak with community representatives about the pipe replacements. He also noted that the company has already paid the fine.

Out of the 900 homes in Brookfield, 153 are served by copper gas lines, and they’ll be replaced with polyethylene piping. Meanwhile, the SCC will conduct its own tests on copper pipes.

“It’s unusual for copper to corrode, so we’re trying to understand what caused that to happen,” said James Hotinger, assistant director of the SCC’s Division of Utility and Railroad Safety. “This knowledge could help people around the country who have copper pipes.”