Lubricating oil that hit hot steam pipes caused the fire at Martin Drake Power Plant on Monday, according to a statement from Colorado Springs fire, which said the blaze was accidental.
Investigators found that the flames were fed by free-flowing lubricating oil that increased the fire's size and severity, Colorado Springs Fire Chief Chris Riley said at a Wednesday morning news conference..
Investigators had not determined what caused the oil to escape and ignite, Riley said.
Riley said high heat and fire caused damage around the power plant building and turbine.
Riley credited firefighters and Colorado Springs Utilities emergency planning for keeping the fire from doing any more damage than it did.
"The silver lining to a large fire that had a very devastating effect on a critical part of our city's infrastructure is that there were no injuries and no fatalities," Riley said.
Riley said the fire reached three levels and spread laterally inside the power plant, which the fire department had not released back to Utilities by Wednesday, citing safety concerns and scattered hot spots.
After fire crews extinguish every flare, Utilities officials will assess the damage and come up with a contingency plan, which Utilities CEO Jerry Forte said is his top priority.
"When it comes to the extent of the damage, what needs to be repaired, how long it will take, we just don't know that yet," Forte said. "Assessors and engineers will arrive in the next day and hopefully by early next week they will be able to start a condition assessment."
The entire plant has been shut down since the fire. Forte said he hopes one or two of Drake's three generators are still operational and the repairs could be phased in to alleviate energy production and cost.
Forte said Drake employees were on paid leave and many were being temporarily transferred to other locations so they could keep working.
Forte said it's too early to determine the amount of oil that flowed into the fire or how the lubricant spilled.
The oil is used to lubricate large ball bearings on the generators' turbines, explained Utilities spokesman Steve Berry. The system continuously lubricates the turbines as they run, but couldn't say how it escaped.
"We don't even know that yet, we just know what the fire department told us from their preliminary findings," Berry said.
The lubrication system is periodically checked according to regulations but there was no information available to indicate whether or not the most recent check of the equipment was successful, Berry said, adding those details would be part of the investigation.
More than 100 Colorado Springs firefighters attacked the fire that erupted about 9:40 a.m. Monday, sending a black plume of smoke over downtown and forcing the evacuation of 62 employees. Voluntary evacuation notices were sent out to almost 800 residents in a three-block area of the plant, fire officials said.