"If you attempt to explain to someone the cause of a fire is Undetermined Accidental. How can that be possible ? To determine you would have to prove No random, spontaneous, or mysterious event has occured. Undetermined Accidental is a contradiction. If the cause is Undetermined It's Undetermined. I wonder if what Steve posted "How do I ever make a call of Accidental" can be answered without adding information that is only probable. That brings you back to Undertimined. The cause is Undertimined. Doesn't "best probable analysis" still really leave you with Undertimined?"

You will not be able to prove a negative. If you always had to prove that a random or mysterious event did not occur, then we are all out of a job. This goes with the idea that "anything is possible" with respect to fire. Not true since the fire has to behave within the laws of science. Steve's recommendation of Carl Sagan's book is a good one.

Going back to a previous postings and assuming that every fire investigator would use the same classification system, you would have to qualify your classification. I would argue that you could have an undetermined cause and still call it accidental by stating a presumption that all fires are accidental until proven otherwise. Without any evidence of an arson fire, you can reasonably determine that the fire was accidental. It might not be the best stand alone classification (i.e. undermined accidental), but I would argue it could be used.

This whole issue arose because of different charges between private and public sector fire investigators. The use of classification needs to be in the context of the charge of the investigator.

Douglas J. Carpenter, MScFPE, CFEI, PE, FSFPE
Vice President & Principal Engineer
Combustion Science & Engineering, Inc.
8940 Old Annapolis Road, Suite L
Columbia, MD 21045
(410) 884-3266
(410) 884-3267 (fax)
www.csefire.com