Its true, there are some tiny amounts of carcinogenic chemicals that are produced when fat hits fire, however most studies have concluded that high heat as in grilling and producing heavily charred meat is the real culprit.
This excerpt comments on a 2009 study, where 60,000 people avg age 63 eating habits were watched for 9 years. Lovers of well done deep charred bbq fared the worst developing pancreatic cancer at a significantly higher rate than all others.
Bottom line, if your tendency is to worry about ambiguous health risks while eating common foods, then BBQ and smoking is most likely not for you. The fact is there are so many elements to daily life that will kill you, there are synergistic effects going on in our bodies that no tests can duplicate which are the result of chemicals from so many things we eat, touch, breath. I'm not telling you to ignore proven science, but those of us that are older can easily remember when those same scientist told us eggs, milk, and butter were bad for you, and since they have reversed themselves. Sometimes the replacement is more harmful than the item they are trying to tell you to stay away from.
You can avoid meat juices and fat from hitting the burning coals by adding a water pan to catch the fat. If you just add a drip pan (the coals will heat that grease and fry it) you will get the same effect of high heat releasing the carcinogens.
The one thing I can tell you for sure at this moment, if you own and use a UDS and a Toyota Prius you have a serious health risk.
