Do polymerized cooking oils release free radicals I am seasoning a carbon steel wok and from what I understand it basically involves heating cooking oil on it until it gets to the smoke point and then forms a polymerized layer that makes it like a non stick pan.  I have also heard that as oil gets heated close to and past the smoke point it breaks down releasing free radicals and other unhealthy compounds.  My question is that when the heated oil polymerizes do these compounds get permanently locked up in the polymer or will they eventually get into the food cooked in the pan?
If you use fresh cooking oil containing unsaturated fats (like olive or canola oil) to season your pan, it will thermally polymerize to form a stable layer that gives the cooking surface its nonstick properties. Note that a saturated fat like coconut oil, lard, or ghee will not work very well or at all for this, since it does not have any double bonds to undergo polymerization. The radical formation you are concerned about results over time from air oxidation of unsaturated fats to form peroxides--these in turn break down to give aldehydes and acids that cause the bad flavor of rancid fat, and have adverse health effects. (Not a problem for coconut oil.) Heating fresh oil in a pan to create a nonstick coating may result in some air oxidation in addition to polymer formation, but I think it is not a big cause for concern. High polymers are generally nontoxic because the body does not absorb them.