Anything can be dangerous if there is enough of it and flour is no exception.
Something not everyone knows is that flour is a highly flammable powder due to its high starch content, which is easily ignitable.
Dust clouds from handling flour can ignite from even a small spark or flame, leading to a fire that can spread quickly.
This video gives a quick visual of the danger. This applies to almost all cooking powders, including sugar and spice.
It’s important to handle flour carefully and to keep it away from heat sources, sparks, and open flames.