South Australian firefighters have extinguished a blaze at an electrical substation near the West End brewery in Adelaide's west.
Emergency crews were called to the fire on West Thebarton Road after reports of flames and explosions about 2:15pm.
Fire investigators are still trying to work out the exact cause of the explosion and are using thermal-imaging cameras to see if there is a fire inside a transformer at the substation.
"At this stage we've been told there is an unlikely risk of [another] explosion," assistant chief fire officer Glenn Benham said.
"There is a risk if the vessel bursts that we could have a running oil fire and we've put strategies in place to ensure that if we get an oil leak that we can contain that and make sure it doesn't harm the environment."
At this stage it is believed a transformer failure caused the initial incident.
South Australian Police said there had been no reports of injuries.
The Metropolitan Fire Service said firefighters had a number of issues to deal with when they first arrived.
"The substation was live and we needed to make sure it had been switched off, both the low and high-voltage electricity that was running in and out of this site before we could enter and start the firefighting operation," Mr Benham said.
There were major traffic problems earlier in the afternoon and buses had to be diverted around the scene.
Nick Budgen was working nearby and heard the explosion.
"Heard this huge explosion, so came out the front to have a look and there were flames, plumes of black smoke and there were multiple explosions," he said.
