Building has been evacuated and all company staff has been accounted for.
The spill occurred Wednesday morning at a Birmingham Water Works plant along a heavily travelled suburban highway.
Automakers were hoping that the plants can return to normal operations as temperatures moderate on Saturday and into next week.
The cause of the blaze remains under investigation.
Explosion was sparked by a fire in a gas pipeline in a coke oven battery complex during scheduled maintenance.
A good electrical maintenance program is based on the new CSA Z463 industry standard.