Hello,
Good question. I will let you know what little I know about this subject and the experience I have had.
I don't know of the legalities when it comes to burning waste oil, so I cant comment on that.
As far as burning waste oil and affecting the neighbors, I am pretty sure my next door neighbor (I live in town) doesn't even know I am burning it. My furnace burns clean with no smoke output. All you see coming out of the stack is heat waves. As long as you don't stick your head right over the stack, you cant smell it either. I have noticed soot buildup in the furnace and in the exhaust pipe, which over time could build up, and I suppose some of that is going air borne, but nothing I have actually seen coming out.
I use my heater to heat the garage, so it doesn't run full time, just occasionally when I want to warm up the garage and work out there. I don't have that many hours on the furnace since the conversion, but in the little time I have used it, I don't see a problem with it bothering the neighbors.
Russ
Oh yea, I am burning WMO