MILWAUKEE - Fire crews responded to the scene of a fire at a construction site near 1st and Becher on Milwaukee's south side around 5:30 a.m. Saturday, Dec. 12.
Neighbors said they were woken up by what felt like an explosion.
"I was sleeping this morning, at about 5:20 the house shook. I heard a big explosion, a big boom," said resident Aaron Gray.
Some people reported hearing it as far away as 27th Street. The Milwaukee Police Department said the explosion was at a construction site, causing the fire.
The Milwaukee Fire Department confirms there were no injuries reported -- a surprise to those who heard it.
"I was just shocked, I was more scared than anything because I didn't know where the noise came from," Gray said.
In a video Gray shared with FOX6 News, flames appear to have been coming out of the lower portion of a parking structure.
The cause of the fire -- or what the explosion sound was that neighbors heard -- is still under investigation.