Q: Is the phenomenon of spontaneous-human-combustion related to Adjuster fusion?

A: Spontaneous combustion happens fairly regularly on earth in some types of organic materials, such as haystacks, oily rags, and coal. Human spontaneous combustion is a phenomenon that occurs rarely, and it is always a source of wonder; however, it is completely unlike Adjuster fusion as described in The Urantia Book. In spontaneous human combustion, there are always remains of the person who is burned, and sometime, the person even survives this ordeal, as it is frequently a slow process. In Adjuster fusion, the body of the fusion candidate is entirely obliterated in an instant, leaving not a trace. That fact alone tells us that human spontaneous combustion has no relation to the Adjuster-fusion experience.

This fusion during physical life instantly consumes the material body; the human beings who might witness such a spectacle would only observe the translating mortal disappear ‘in chariots of fire.’ (110:7.2)

To read more about the fusion experience, please see Death and Translation. This section of The Urantia Book describes in more detail the events surrounding Adjuster fusion on a world that has been settled in Light and Life. Needless to say, it is not a common occurrance on our planet. As far as I can tell, only once has this occurred an Earth, and that was to Elijah, a truth-teacher in the tenth century before Christ.

This event is also mentioned in the Bible: ( 2 Kings 2:1-12 (New American Standard Bible)

Elijah is now one of the Four-And-Twenty Counselors who serve on Jerusem.

Thank you for this interesting question.