Which serious outcome is commonly linked to spontaneous human combustion?

The phenomenon of spontaneous human combustion (SHC) is characterized by a person being consumed by fire without an apparent external source of ignition. This outcome suggests that an individual might ignite and burn completely due to internal factors or processes, rather than from an external flame or ignition source. The concept of complete incineration without external ignition is central to the definition of SHC and is often highlighted in discussions about this controversial and rare occurrence.

In contrast, severe burns on extremities typically result from external sources, and while a reduction of oxygen in the environment can influence combustion, it does not align specifically with the concept of SHC. Likewise, increased exposure to toxic fumes may result from fire incidents, but it does not describe the primary outcome associated with spontaneous human combustion itself. Thus, the focus on complete incineration without an external ignition source is what distinctly marks this phenomenon in fire investigation discussions.