Oklahoma: Lightning Hits Glenpool Gasoline Storage Tank

A lightning strike ignited a fire in a gasoline-storage tank at the Explorer Pipeline Terminal in Glenpool, OK, on June 12, 2006. The incident involved Tank 373, on the east side of the tank farm. The tank was constructed in 1970 with a welded steel-cone roof. It was 140 feet in diameter and 48 feet high, and could store up to 128,319 barrels (nearly 5.4 million gallons). In 1977, an internal aluminum floating deck was installed in the tank.

Eleven minutes before the lightning strike, the tank was filled to a height of 43 feet with approximately 117,000 barrels (4.9 million gallons) of blended gasoline. This was the second tank fire at the facility that the department had responded to in three years, but the largest facility fire in the fire department's 100-year history.

The Glenpool Fire Department was dispatched to a reported "tank fire" at 9:07 A.M. Responding on the initial alarm were Glenpool Engines 1 and 3 with seven firefighters under the command of Captain Clay Ward, who reported that a large fire was visible from over a quarter-mile away. Within four minutes of the lightning strike, Explorer Pipelines staff started the facility's emergency fire pumps and placed fixed monitors into operation in an effort to keep nearby tanks cool, as well as to keep the burning tank cool to prevent it from collapsing. Facility employees also notified key company personnel.

Upon arrival, Ward requested all available Glenpool firefighters respond to the scene. He also called for mutual aid from the Bixby and Jenks fire departments. Ward established command and designated a staging area for mutual aid departments. Fire Chief Paul Newton arrived on scene at 9:23 A.M. and assumed command. Upon assessing the situation and identifying the potential risks to the 10 to 15 adjoining homes, a voluntary evacuation was requested. Newton immediately requested additional resources from the Sapulpa and Tulsa fire departments and the Tulsa Area Emergency Management Group. The majority of the specialized equipment that was needed to extinguish a fire of this type was staged at the Sunoco Refinery in Tulsa.

Defensive operations were initiated upon arrival of the fire department. Initial efforts were focused on eliminating potential ignition of exposures consisting of adjacent tanks filled with gasoline. Cooling streams from Explorer's fire protection system protected the other tanks. Explorer's fire protection system consists of a 1.26 million-gallon water supply tank, electric and gasoline-driven fire pumps and a network of six-inch water mains that supply 33 hydrants throughout the facility. All hydrants are equipped with deluge monitors.

While additional local personnel and equipment were arriving, a telephone conference was held by incident commanders, Explorer personnel, Sunoco officials, and Williams Fire and Hazard Control. This briefing was beneficial to all in regards to understanding exactly what confronted them in extinguishing this fire. This was a very large internal floating roof tank that would require extensive coordination between the facility and emergency personnel. There is less experience in the industry in fighting fires of this type due to the infrequency of occurrences. The condition of the cone and the floating roof were important in determining the tactics to be used. After a risk-versus-benefit assessment, it was decided to remove some of the product from the burning tank.

At 11:16 A.M., command was notified of an approaching thunderstorm with heavy downpours lasting up to one hour. Luckily, this storm passed north of the incident and did not affect firefighting operations. While waiting for Williams Fire and Hazard Control officials and equipment to arrive, incident commanders utilizing mutual aid resources established two additional water supplies to supplement the facilities water supply.

Product was removed from the tank by simultaneous gravity transfer to other tanks and by pumping into a 24-inch outbound pipeline. Careful monitoring of the gasoline temperature was done and when the temperature reached 117 degrees Fahrenheit, the transfer was stopped. Pump seals and bearings are monitored by thermal probes and the system automatically shuts down at 130 degrees.

Two supply lines were established to Williams' 6,000-gpm portable pump at the scene. Side A had a 1,200-gpm flow pumped through Tulsa Fire Department Engine 25 and Glenpool Squad 1. Side C had a 1,500-gpm flow pumped through Glenpool Engine 1 and Jenks Engine 1. An additional engine was on standby at each location in the relay where a pumper was inline in case of an equipment failure.

The offensive attack was initiated at 6:15 P.M., and it took about 90 minutes to extinguish the fire. During the attack, water and foam application was 3,400 gpm. Some 306,000 gallons of water and 3,060 gallons of foam concentrate were used. The Thunderstorm ATC 1 X 3 foam was proportioned at 1% with an application rate of 0.19%. Officials estimated that 600 gallons of foam extinguished 97% of the fire. The balance was used on the remaining hidden fires and to cool areas under the cone roof and damaged tank shell.

The fire was declared under control at 7:01 P.M. Due to the heat and type of tank construction, there were many factors that could cause a re-ignition. At 9:02, mutual aid departments were released; at 10:13 P.M., Glenpool Command was terminated. At this time, security and the fire watch were turned over to Explorer employees. The fire was out at 8:45 P.M., but due to the potential for re-ignition, it was not officially declared out until 7 A.M. on June 13.

The transfer of product and fire suppression resulted in approximately 94,000 barrels (3.9 million gallons) of gasoline being saved and approximately 23,000 barrels (966,000 gallons) lost. The tank was destroyed and damage to the contents was estimated at $3.1 million. Weather at the time was typical for summer with the high temperature in the 90s and scattered thunderstorms. During the incident, the weather varied greatly from hot and humid to cool breezes with rain.

Three months before the fire, the fire department toured the Explorer facility while a tank was being refurbished. This let firefighters and staff review pre-plans of the facility. Each platoon of firefighters visited the facility to gain first-hand knowledge of the site and review Explorer's emergency plan. The largest problem that was identified during pre-planning was water supply. Water flows in the area were adequate, but difficult to access, requiring long hoselays. Mutual aid resources were required to lay several thousand feet of supply line through rough terrain. This was accomplished by loading large-diameter hose onto brush trucks and deploying them off-road.