Throughout most of the 20th Century, textiles reigned supreme over the industrial scene in Greensboro, North Carolina, population 258,000. But when Greensboro Fire Department Assistant Chief David Douglas took up his profession in the mid-1970s, the region's changing economy required that responders deal with new industrial challenges as well.
"Obviously, textiles have taken somewhat of a hit," Douglas said. "If I had to classify our economy, I'd say we were in transition from manufacturing textiles and furniture into a transportation hub. Two major interstate highways run through Greensboro. We are more or less located in the center of the state."
However, one critical commodity that moves through Greensboro is no slave to the interstates. Two major fuel pipelines serving the eastern United States pass through Greensboro, with many local pipeline terminals and fuel storage facilities. One tank farm located in Greensboro is among the largest in the world for storage of refined petroleum products. Available storage capacity in Greensboro is estimatedto be about 1 billion gallons.
On June 13, 2010, a gasoline storage tank at Colonial caught fire apparently afterit was struck by lightning. The Greensboro Fire Department extinguished the firewithin six hours and protected other nearby tanks from becoming involved, earning accolades from the local media for its speedy response.
"That so many people safely awakened hours later, not knowing the event hadeven happened, bears testament to the speed and effectiveness of the response," according to an editorial in the Greensboro News & Record.
Colonial Pipeline delivers an average of 100 million gallons a day of refined petroleum products across the southern and eastern US. Built in 1963, Colonial's Greensboro facility is the largest of the company's 15 tank farms nationwide. Located less than a mile from the airport, the 76-tank facility is also the largest or Greensboro's many terminals. Although the tank farm has many light manufacturing neighbors, the area remains largely free of residential development.
As far back as the 1970s, Colonial opened its doors to local firefighters trainingto protect its tank battery and similar facilities nearby. However, in 2002, Greensboro firefighters redoubled their efforts to better protect these facilities by successfully applying for a Homeland Security grant to buy specialized equipment.
"Actually, the pipeline companies and some of the terminals funded our portion of the grant," Douglas said.
Greensboro FD purchased a Williams Fire and Hazard Control trailer-mounted 6,000 gpm pump, 10,000 feet of 7¼-inch hose, a trailer-mounted Williams F&HC Ambassador 1,000 to 6,000 gpm nozzle and a Williams F&HC Daspit tool, a 500- to 2,000-gpm nozzle that can operate from a rim-mounted, truck-mounted or "throwdown" base. Firefighters also purchased one ring main manifold with multiple outlets under the DHS grant to replace traditional fire hydrants protecting their industrial facilities.
Colonial took fire protection measures beyond that, Douglas said. The company took it upon itself to buy two additional manifolds for use at their facility in addition to the one covered by the grant. The City of Greensboro Water Department agreed to install the ring main manifolds at no charge for facilities that bought them. Also, Colonial stocked 2,500 gallons of firefighting foam on site in addition to 1,750 gallons that the Greensboro FD keeps at one of its fire stations.
"Each year, we take all three of our shifts and put them through a training program specifically at Colonial," Douglas said. "Special ops tries to come up with some pipeline scenario that we have to address. We train in conjunction with Colonial so that their personnel react and respond in conjunction with us."
Greensboro firefighters trained at the Colonial facility as little as three weeks before the fire. A typical training exercise might involve drafting from the fire protection water pond deep in the tank farm, he said.
"We go off a static water supply there as opposed to coming off our municipal system," Douglas said. "We extend hose lines throughout the tank farm to determine our reach." Firefighters also familiarize themselves with the process of how storage tanks are filled and emptied, as well as the actions taken when a high-level alarm sounds.
"Our involvement with Colonial is very extensive, much more so than with the other terminals in our city," Douglas said.
Thankfully, except for a single storage tank seal fire 30 years ago and the occasional tanker truck blaze, Greensboro firefighters have been spared from exercising their bulk flammable liquid firefighting skill in earnest.
That lucky streak ended June 13.
Shortly before midnight, a major storm front hit Greensboro complete with hard rain, vivid lightning and tremendous thunder, Douglas said.
"This had gone on for somewhere upwards of an hour," Douglas said. "It was the kind of storm that will wake you up from a sound sleep."
Colonial protects its tanks with systems designed to deflect electrical chargesinto the ground. Security cameras reveal that late in the brief storm, a tremendous lightning strike came down in the area of the tank battery, Douglas said. There seems little doubt that the lightning hit the tank and the electrical grounding system failed to prevent a fire.
At the first indication of problems, the control room at Colonial dispatched two employees to investigate. The employees radioed confirmation that Tank No. 819 was burning, Douglas said. The control room immediately contacted 911. At the same time, personnel began closing valves so that if the tank breached, product would not flow out of the surrounding dike. Such a breach has never been known to happen.
"They did everything they were supposed to do," Douglas said.
As usual for a storm like this, the lightning set off alarm systems across town, Douglas said. Dispatchers were dealing with a flood of various alarms when, at 12:47 a.m., the first report about the Colonial fire came in.
Due to the overcast, the night was still extremely dark. While the rain continuedat least half an hour after ignition, the wind from the thunderstorm had ceased. Billowing fireballs from the burning tank were masked by a heavy plume of black smoke that initially rose straight up, Douglas said.
First arriving units found a tank on fire with fire showing through the geodesic dome. After the first arriving officer made his 360 degree assessment the fire expanded to cover the full surface of exposed fuel.
In a battery with tanks as large as 180 feet in diameter, the lightning had thankfully struck one of the smallest — an 80-foot-diameter floating roof tank standing 51 feet tall, Douglas said. It was only half full, holding about 924,000 gallons of gasoline. Almost immediately, the fire burned away an aluminum geodesicdome atop the tank that traps escaping vapor.
"As the fire burned for a while, it got a little hotter and the combustion became more complete," Douglas said. "The fireball became a little more visible than the smoke plume."
In addition to losing the geodesic dome, the tank eventually lost its floating roof. Douglas said he believes the moment it sank was captured on video. "Part of the tank gives way," he said. "You can see an eruption of flame comparable to a boilover. We believe that has to be when the top sank."
The moment occurred long before any foam was applied to the tank, Douglas said.
"We didn't sink it."
Firefighters arriving on the scene took immediate steps to establish water supply to two monitors on the dike wall and two fire department portable monitors, he said.
"We were also trying to establish our Ambassador nozzle to get big water on the exposures," Douglas said. "The tanks east and west of the fire were officially described as empty. In fact, there were about 3,000 barrels in each one." Spaced about 51 feet from the burning tank, these exposures would be the focus of the department's water and firefighting efforts until preparations were in place for a foam attack.
The department's foam task force was instructed to gather its special equipment from various locations. This Task Force includes units from three fire stations near the tank farm. Protocol also required contacting the Charlotte Fire Department 85 miles away for a second extinguishment.
"Charlotte has a tank farm that isn't nearly as large as ours, but we knew from collective training that neither of us had enough available foam for a sustained attack alone," Douglas said. "One of the first things we did after establishing our unified command was to notify Charlotte to respond with their foam task force."
At the same time, Colonial ordered a cache of foam located at its Spartanburg, South Carolina, facility to be brought in.
"Colonial is far and away the most prepared oil company in Greensboro for just this type of event," Douglas said. "Some of the other terminals, especially those that have fixed systems on their loading racks, have their foam in tanks, not totes. Colonial is really the only one that has appreciable foam in totes."
Timing was another lucky break. At 1 a.m. on a weekend, a minimum of traffic helped firefighters respond quickly. It also allowed law enforcement to quickly close the nearby interstate highway. The closest access to the burning tank was from the bottom of an I-40 exit ramp.
The early hour gave firefighters still another advantage; nearby businesses that ordinarily use large volumes of water were closed.
"We had an excellent set of circumstances all the way around," Douglas said. "If you handed me a piece of paper and said 'You're going to have a tank fire tomorrow — write down all the ideal circumstances you want to have,' I don't think we could have hit them all."
On the negative side, Greensboro firefighters were simultaneously dealing with a working fire on the 10th floor of a high-rise residential building on the other side of town. The department was also working two residential structures struck by lightning. The neighboring city of High Point and surrounding Guilford County fire departments provided several engines to backfill outlying fire stations in Greensboro during the emergency. Greensboro FD brought in off-duty personnel to operate reserve apparatus assigned to other areas of the city.
"We were stretched about as thin as you could get without breaking," Douglas said. "But we didn't break."
At the fire, except for protecting exposures, responders were mainly waiting forfoam resources and equipment to arrive.
"Once the equipment arrived, our 6,000-gpm pump was connected to the ring main manifold," Douglas said. "A foam supply was established and about 1,800 feet of 7¼-inch line was laid from our water supply point down to where we had our Ambassador nozzle and Daspit tools on the ground."
With that done, Colonial began to empty the involved tank at a rate of about 5,000 barrels per hour. The drawdown ceased well before the foam application took place.
"The engineers with Colonial said the only concern they had about the tank collapsing is if the fire got down to the last horizontal weld," Douglas said. "If there was a tank failure at that point, we would lose the contents into the dike. Our intent was to bring the liquid level down to around 10- to 12-feet before we initiated an attack, giving us optimum probability at extinguishment on our first shot. "Drawing down the tank was also being coordinated with the imminent arrival of extra foam from Charlotte.
"We didn't want to exhaust our foam supply (in Greensboro), not be successful in extinguishment and have to start from scratch with the foam from Charlotte," Douglas said.
At 6:20 a.m., only five minutes before the foam from Charlotte arrived, firefighters were in position to launch an attack. Using the NFPA recommended application rate of 804 gallons per minute at 0.16 gpm per square foot, the estimated time to knockdown would have been 65 minutes. Instead, Greensboro firefighters cranked their Ambassador nozzle up to 2,000 gpm at 0.45 gpm/sq.ft.
The speed with which knockdown was achieved stunned everyone, Douglas said.
"I had just completed an interview with the local media," he said. "Like I promised, I gave them a heads-up once we initiated the foam attack. Before they could cut back from commercial, we had the tank knocked down."
Based on raw video taken at the scene, knockdown was achieved in one minute and 18 seconds. Final extinguishment was a bit more complicated due to the sunken roof and collapsed portions of the tank.
"One side of the roof crumpled like an accordion while the other side sat down flat," Douglas said. "Underneath that side we had an amount of incipient fire that our overhead attack wasn't reaching."
Firefighters flowed foam with the Ambassador for about 15 minutes after knockdown until final extinguishment.
"We were taking heat readings off the tank the entire time," Douglas said. "Wewere very confident about what we were doing. We didn't feel we were doing anything that subjected our people to any extraordinary danger."
Douglas continues to stress that Colonial Pipeline had a tank fire, not a tank explosion.
"We have always struggled against the notion that if something happened outthere it would be a catastrophic, cataclysmic event," Douglas said. "There mightbe a fire, but not an explosion. These are just storage tanks. They are not under pressure.
"I don't want to minimize the risk but, by the same token, I've been in building fires that presented a lot more danger than this did.
Editor's note: This after-action review appeared in "Disasters Man-Made" by David White and Anton Riecher that was published in 2011.