Fowler Associates Labs

Guam Tanker Fires Linked To Static Electricity

ESD Journal Editor's Comments: Air flow by itself does not cause static charging to any significant degree. The particulate materials in the strong wind such as sand could have caused the static charges. The motion of the lid on the tank could have caused the static charges. Regardless of the exact method, the wind played an important roll in this static explosion.

HAGATNA, Guam - A buildup of static electricity may be the cause of the fire at the commercial port tank farm in Piti that erupted when Supertyphoon Pongsona pounded the island in December of last year.

The fire started at the Mobil tank facility when two tanks, one with gasoline and the other with jet fuel, caught fire. Guam Fire Chief Felix Sablan said oil officials have told him a full tank of fuel could take four days to burn out.

Static electricity may have occurred inside the tank due to friction caused by extremely high winds rushing through the ventilation system, according to Guam Fire Department Capt. Darren Apiag.

The fire burned for six days, and consumed four of the petroleum company's fuel storage tanks and caused officials to shut down gasoline sales to the public. Roads were nearly deserted until officials lifted the restriction on Dec. 15. After the restriction was lifted long lines formed at service stations all over the island as residents waited to buy gasoline.

Apiag said the tank that first caught fire contained less than 15 percent of its total capacity of unleaded gasoline when the fire erupted. That situation, he explained, is considered to be unsafe in adverse weather conditions due to the high accumulation of gasoline vapors inside the tank.

He said according to Mobil officials, the tank was previously damaged in July, during typhoons Chata'an and Halong. The tank’s side walls were damaged, preventing the free-floating internal roof from moving no more than seven feet from the bottom of the tank.

"Therefore preventing the tank from being filled with product or water," Apiag said. "This is a safety practice during adverse weather conditions."

Based on the high volume and speed of air travel within the tank, it is likely unacceptable levels of static electricity may have built up and eventually ignited the fuel vapors within the tank, Apiag said. The explosion sent the tank's lid airborne, and it landed more than six hundred feet northeast of the tank, Apiag said.

Cecile Bamba Suda, public relations and government affairs manager for Mobil Oil Guam Inc., issued the following statement: "Mobil is currently assessing the preliminary report, as well as other information. As such, we believe it (is) inappropriate and premature to comment on any statements."

"Mobil has conducted an investigation into the fire, which will form part of a broader review of the impact of Supertyphoon Pongsona on all of Mobil operations on Guam," Suda said. She also stated that the investigation is ongoing and could not say when it will be completed.

Company officials have received a part of the fire department’s report, Suda said.

"We are currently reviewing the preliminary report," Suda said. "We appreciate the input of GFD and we will give it appropriate weight in our own investigation."

"Safety procedures are in place at the terminal. Mobil is committed to safe, responsible operations," Suda said. "We will continue to work closely with GFD in relation to fire ... response."

Paraphrased by Steve Waldrop
February 20, 2003