Fire crews battled a potentially explosive fire at the Akzo Nobel Chemical Plant in Saskatoon this morning.

The lone security guard at the plant at 3910 Wanuskewin Road called 911 just after 4 a.m. CST to report flames shooting from a vent stack on a tank, said Assistant Fire Chief Wayne Rodger.

The tank contained about 3,700 kilograms of a combustible fuel additive. It was a liquid and not stored under pressure.

Rodger said the crews were trying to keep the tank cool enough so that the contents did not ignite.

"With the staff at Akzo Nobel, we're attempting to cool the fluid that's inside the tank, and we continue to do that as we speak," Rodger said.

"At least if it's burning at its termination point, we have control over it because we know exactly what it's doing."

Seven fire trucks, paramedics and the HazMat truck all massed at the plant.

Police closed off all roads around the plant, affecting traffic on Wanuskewin Road, Arthur Rose Avenue and 71st Street.

There were no injuries reported.

Fire investigators are working with Akzo Nobel staff to determine what caused the combustible fuel additive to ignite.

Preliminary damages are estimated to be $20,000.