Do polymerized cooking oils release free radicals
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.