heres the thing,
I have never used any other fuel except normal lamp parrafin in the 2 years i've been doing fire poi.
So far while on this site i have heard mention of people using kerosene and all manner of other dangerous sounding fuel (threads on major burns accident, carcinogens etc etc etc)
So (to the point), The other day i was spinning in the back garden at a friends house party. The routine was going better then ever and i even threw in some body, arm and leg wraps for the first time on fire. Then when doing the weave, i messed up (i really dont know how), and one of my poi hit me in the face, while still fully ablaze.
Yet as if by a miracle, i wasn't even remotely burned. And all i had to show for the accident was a small smear of carbon under my cheek 
so, after conducting several tests, i realised that it is almost impossible to burn your self with parrafin. It burns at a really low temperature(it does however heat up metal components), Its not carcinogenic (a doctor friend of mine assures me that people used to be proscribed it to cure stomach ulsers etc), and it doesn't seem to have a drastic effect on wild life like other petrol esk fuels.
so heres my point. Use parrafin. 