Just reading about a possible cause of kidney cancer being; Polycyclic aromatic hydrocarbons (PAHs) a group of over 100 different chemicals that are formed during the incomplete burning of coal, oi, wood, gas, garbage, or other organic substances like tobacco or charbroiled meat. PAHs are usually found as a mixture containing two or 8more of these compounds, such as soot. I have kidney cancer, I work with soot everyday and have for over a decade. I put out brush fires and trash fires and out of control camp fires for a living. Funny nobody ever brought this up at fire fighter training. It is okay as they will blame my excess weight from grilled meat cooked next to my asbestos shingle house I grew up in. However it is amazing how some jobs have a clear link to cancer and nobody talks about it. You have to read it on wikipedia.