Chief Ken Smith, Jr. of the Marcus Hook-Trainer Fire Department, says he does not know why the children were in the building.
"They have all been found and they are all home safe right now," said Smith.
The call came in for a fire on the 200 block of East 10th Street just before 6 p.m.
The view from Chopper 6 captured the raging fire burning through the building that was set to be demolished to make way for a large distribution warehouse.
Eighty to 100 firefighters from all over Delaware and Chester counties and New Castle, Delaware were called in to battle the blaze.
Chopper 6 back over #MarcusHook as fire continues to burn inside of a warehouse. Happening on the 200 block of East 10th Street. @DannCuellar will have an update on Action News at 11pm. @6abc pic.twitter.com/65G9bKKTEd— Chuck McDade (@Squared6abc) November 2, 2021
The warehouse, which officials say is about 80 years old, had a lot of old timber materials, fueling the flames and making people nearby very nervous.
"Oh it was bad man, it was bad," said neighbor Dave Bernard.
"It's scary, my house is right behind this building," said neighbor Amanda Lavallee.
The fire appeared to be under control Monday evening, but ramped back up late in the night.
"It's actually kind of scary because they're not being able to control it very well right now. It keeps igniting," neighbor Pam Verdi.
The fire was eventually placed under control. However, crews remained on the site early Tuesday morning to put out hot spots.
The cause of the fire is under investigation.