Vapors, Storage Tanks, Static Electricity = Catastrophic Explosion.

This photo provided by Nathan Hergert shows a fire burning at an oil and gas drilling site near Greeley, Colo., on Tuesday, March 4, 2014. Static electricity is being blamed for the massive explosion and fire at the oil and gas drilling site north of Greeley that injured two workers. 
(AP Photo/Nathan Hergert)

Oil-and-Gas Explosion North of Greeley, Colorado Results in Two Minor Injuries 

By Monte Whaley The Denver Post Posted: 03/04/2014 10:44:09 AM MST 

Fire crews used a foam retardant to mostly extinguish a massive fire at an oil-and-gas-drilling site north of Greeley on Monday night. 

An explosion that could have been started by static electricity rocked neighbors out of their beds at about 11:20 p.m. Monday. 

The resulting fire was seen for miles. "We were getting ready for bed, and the whole house shook," said Liz Hegert, a resident in the area, told the Greeley Tribune.

The fire came from a drilling site about 2 miles east of Lucerne near Weld County Roads 27 and 70. The Eaton Fire Protection District as well as crews from Windsor-Severance Fire Protection District and the city of Greeley responded. 

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The exact cause of the blaze has yet to be determined, he said. But it could have started as workers were pulling a water/oil mixture out of storage tanks on site to take to a separator.  Static electricity may have set off the vapors. 

 "That is a distinct possibility," Kane said.