'accidental cause' is correct and usable in written English.
You can use it when referring to an undesired event resulting from an unintentional action or unforeseen circumstance. For example: "The accidental cause of the fire remains unknown."
If the investigators rule out an accidental cause, they will search for arson clues using dogs trained to detect the odors of gasoline and other accelerants.
We scientifically tested every feasible accidental cause and were unable to recreate conditions that would cause a conflagration similar to what occurred on Iowa.
A fire that severely damaged the Hekhal Haness synagogue in Geneva in the early hours of May 24, or Shavuot, the Jewish festival, was deliberate, the investigating magistrate, Michel Graber, said, ruling out an accidental cause.
New York City fire investigators believe that one of the deadliest fires in the Fire Department's history can be traced to a purely accidental cause: two teenage boys, roughhousing on Father's Day, knocked over a can of gasoline in the backyard of a hardware store in Queens.
The thing in a sense is and in a sense is not moved by one who moves what is obstructing and preventing its motion (e.g. one who pulls away a pillar from under a roof or one who removes a stone from a wineskin in the water is the accidental cause of motion): and in the same way the real cause of the motion of a ball rebounding from a wall is not the wall but the thrower.
But the fire service said there was nothing to indicate anything other than an accidental cause.
The explosion was accidental, caused by workers accidentally breaching a propylene pipeline.
Rick Saltsman said, "All natural and accidental causes were ruled out".
The state fire marshal ruled the fire accidental, caused by sparks from a machine.
His family dismissed the possibility of natural or accidental causes of death.
Five separate pathologist reports into the case agree that Carol Tucker died of accidental causes.
