Residents who live near the Cleveland Metroparks Zoo may have been woken up to the sound of explosions on Thursday.
WATCH video of the junkyard fire in the media player above.
That's because there were 30 to 50 cars on fire in a salvage yard located under the Pearl Road Bridge.
The Cleveland Fire Department worked in the early morning hours on Thursday to put out the fire.
Cleveland firefighter Mike Norman told News 5 they do not believe the fire was an arson.
"My understand from talking to the Battalion Chief is that they were working in that area earlier in the day, doing some welding and some things that may have led to an ignition source," he said.
However, the fire and smoke were considered dangerous. Norman said they've recently changed protocol within the department, to protect firemen from the fumes and the health risk.
"That's very toxic smoke, we've had a spike in cancer rates in the fire service, so we are having our guys wear their masks as they're fighting even a car fire outside," he said. "Just protect themselves because that winds shifts and you get that smoke in your lungs it can be bad for you."
— Mike Vielhaber (@MVielhaber) November 30, 2017