A ferocious fire which ripped through a Bunnings store in Perth overnight, collapsing the roof and sparking a chemical warning, has been contained.

About 30 firefighters remained at the building in Inglewood this morning to control the blaze after it broke out about 9pm, with huge plumes of toxic smoke blanketing the area.

Multiple explosions were heard for about 40 minutes as aerosol cans were flung up to 50 metres from the building.

The ferocious blaze has sent large plumes of toxic smoke into the air. (9NEWS) (9NEWS)

It is believed the fire started in the air conditioning unit. (Twitter)

Up to 100 people were evacuated from surrounding streets and a nearby night market, with video showing residents on their roofs as they tried to prevent embers from reaching their homes.

Clint Kuchel from the Perth Fire Service earlier said there were concerns the fire could spread.

About 30 firefighters are battling the blaze at Inglewood this morning. (9NEWS) (9NEWS)

The fire broke out about 9pm last night (9NEWS). (9NEWS)

“There are LGP cylinders, pesticides … all sort s of things within the building itself so there is potential for flare ups,” he said.

Several pressurised gas canisters in the building were also unaccounted for, posing a further threat.

“The structure has been weakened by the fire so there is potential for structural collapses," Mr Kuchel said.

“Crews are still in defensive mode at this time.”

Residents were seen on roofs, trying to prevent embers from reaching their homes. (9NEWS) (9NEWS)

Firefighters have evacuated residents on Seventh Avenue and Eight Avenue as a result of structural damage and an evacuation centre has been established.

The Department of Fire and Emergency (DFES) said nearby residents may still be impacted by smoke and fumes, urging them to stay indoors with doors and windows closed and air conditioners turned off.

People have been advised to stay away from the area and to remain aware of fire and emergency services working onsite.

A number of roads have been closed, including Beaufort Street, which has been reduced to one northbound lane between Central Avenue and Ninth Avenue.

Fire investigators will today work to determine the cause of the fire, but authorities believe it may have started in the air conditioning unit.