Transformer burning in Phoenix; no power outages

Posted: Updated:
By Catherine Holland By Catherine Holland
By Catherine Holland By Catherine Holland
By Catherine Holland By Catherine Holland
By Catherine Holland By Catherine Holland
By Catherine Holland By Catherine Holland

PHOENIX -- A transformer has been burning at an APS substation in North Phoenix since late last night.

It's not clear what sparked the massive fire, but it started at about 10 p.m. Monday at Pinnacle Peak Road and 67th Street. Residents reported hearing a large explosion and seeing a fireball shoot into the sky.

Aerial video early Tuesday morning showed massive flames shooting 20 to 30 feet into the air and a huge plume of thick black smoke pouring off the fire. That smoke, which has blown quite some distance, is visible for miles.

Several ADOT cameras showed layer of smoke from the substation fire hovering high over the North Phoenix/Scottsdale area.

According to Capt. Scott Walker of the Phoenix Fire Department, some 40,000 gallons of mineral oil are fueling the fire. That's why the plume of smoke is black. Mineral oil is a nontoxic substance that is often used as a coolant and conductor in electrical transformers.

The area that's burning is about the size of half of a football field.

Mark Shaffer of the Arizona Department of Environmental Quality says there are no major health risks associated with the smoke coming off the fire because mineral oil is not toxic.

"It's a very inert kind of oil," he explained. "We're not talking about hazardous air contaminants in relation to this fire. ... We are fortunate because this is mineral oil."

Shaffer said schools downwind of the fire have been notified as a precaution, but the smoke is expected to remain too high to cause any issues.

Firefighters on the scene say they are going to let the fire burn itself out, which could take several hours at least. The fire is burning in a container right now. The concern is that spraying foam on the fire will cause the container to overflow, allowing the oil and flames to spread.

Crews did try to spray water on the fire earlier, but the heat is so intense it evaporated the water before it could even reach the flames.

While there are no power outages reported, Pinnacle Peak Road is closed between Tatum Boulevard and Scottsdale Road. That closure is expected to remain in place through the morning rush hour.

Pinnacle Peak Road is a major thoroughfare for those living in North Scottsdale and the Desert Ridge area. 3TV Traffic reporter Gina Maravilla advised drivers to allow plenty of extra time for their commutes and to use Dynamite Boulevard, which is to the north, or Loop 101 as alternates.

That road closure appears to be the fire's biggest effect on residents in the area.

Firefighters on the scene said there is no immediate threat to the neighborhood and no evacuations have been ordered. The nearest home is about a mile away.

APS is working on de-energizing the substation, which houses nine transformers, to allow the firefighters to go in as needed. APS officials say de-energizing the plant is more than involved than just flipping a switch. Crews are transferring power out of the station in a manner that does not affect APS customers.

Firefighters are keeping a close eye on the fire to make sure the flames stay contained.

An investigation into what caused the fire will be launched once the flames have died out and it's safe to go into the affected area of the substation. APS officials say it was likely a mechanical issue, but they can't be sure about that until the investigation is complete.