That blackass smoke tells me the place was made with a whole lot of stuff that starts with “poly-—.”
You’re right. That looks like some type of polymer burning. Concrete and rock wool insulation certainly don’t burn and that’s way too much smoke just for paper and office furniture.
The back side of the building doesn’t look so burnt so hopefully people could get out.
That would be a horrible death inhaling all that smoke with no escape.
My heart goes out to any people trapped there. It is more likely they would survive the flames than the fumes.
Office space inside a giant stick of oil. What could go wrong?
God help the poor folks inside that building.