NEW WESTMINSTER, B.C. -- A massive fire at a New Westminster, B.C., recycling plant is now being treated as potentially suspicious.

"It is somewhat suspicious due to the fact that it was raining for the last two days quite heavily, no electrical outlets present," says Assistant Deputy Chief Rob Dick of the New Westminster Fire and Rescue Services.

"The fact that the fire started with no real cause, we are treating it as a suspicious fire at this point," he explained. No accelerant was found at the scene but investigators are reviewing surveillance video.

The recycling facility was closed when the flames broke out shortly after 7 p.m. Monday. The blaze began in piles of recyclables.

"We looked out the window and it started to get out of control real quick, like in a matter of minutes," said Jessica Finlayson, who lives nearby.

Dan Millar also lives in the area, and described seeing flames "just leaping into the air."

“The smoke was black and it was all lit up by the fire,” he told CTV News.

Fire crews rushed to the scene, quickly upgrading it to a four-alarm fire.

"Given the fuel load that the plastic presented it quickly spread to the remainder of the material," said Assistant Deputy Fire Chief Curtis Bremner.

Firefighters from Delta and Richmond were brought in to assist.

Crews used ladders from multiples trucks to fight the blaze.

"The fire was several hundred feet long by, 150 to 200 feet long by 30 to 40 feet wide and several pallets high of baled plastic bottles and that sort of material," Bremner said.

The massive flames and plumes of smoke could be seen throughout the Queensborough area and beyond.

The incident is the second major fire to rock the city in one month. In late September, after 12 days of work, firefighters finally extinguished the Pier Park fire that destroyed a large chunk of the city’s waterfront park.

Neighbours say they were shocked at how high the flames got on Monday night.

"I’m thinking should I start watering my roof so our house doesn’t catch on fire? I’m really glad that black smoke … (is) actually superseding our house and going off into the distance because it looks scary," Finlayson said.

The City of New Westminster tweeted a warning to residents Monday night, advising them to close their windows closed and remain indoors.

Resident Devinder Singh Grewal said it was "hard to breathe" and "really smelly.”

"Smoke is a hazardous material, so every fire creates a cocktail of toxic chemicals. Plastic does create an additional concern, respiratory concerns," Bremner told CTV News.

He says crews got a hand from mother nature.

"The rain certainly helps suppress the smoke and vapours from the fire. It doesn’t really add much to extinguish the fire, but it certainly does suppress the vapours for a fire like this," he explained.

More than 40 firefighters were working at the peak of the fire, they managed to contain the flames several hours later.\

“There’s damage to the exterior of the building due to the radiant heat from the fire and overhaul we had to perform inside to ensure there was no extension inside the building. So drywall was taken down to ensure the fire hadn’t extended into the walls,” Assistant Deputy Chief Rob Dick said.

Crews remained on scene through the night to monitor hot spots.

"They did a great job, worked really hard, probably mitigated a lot of loss in that property adjacent to it. It was a long, nasty fire, lots of hard work and they did a great, great job," Bremner said.

With files from CTV News Vancouver’s Angela Jung and Peter Bremner