1.
sparks, flying embers
Small particles of burning material that fly through the air from a fire. Also used figuratively for trouble or conflict that spreads to or affects uninvolved parties.
Usage
Often used figuratively in the expression 降りかかる火の粉は払わなければならない, meaning "you must deal with trouble that comes your way" — i.e., you cannot ignore problems that affect you even if you did not cause them.
The figurative use of 火の粉 refers to the fallout or collateral effects of someone else's conflict or scandal reaching you.