Tulsa firefighters dealt with a dangerous situation Wednesday afternoon at the Gateway Market at Pine and Peoria.
When they arrived at the grocery store, they found the fire around back.
A cardboard container and large electrical transformer were burning.
The engine's captain, Keith Back, said electricity was arcing, forcing his crew to come up with a different plan of attack.
"We use the CO2 extinguisher on it and things like that to get the fire put under control and also keep us at the same time, you know, keep up from getting any electrical shock or anything," Back said.
Investigators are still working to determine whether the fire started in the cardboard bin or the transformer.