The issue w/ Pink Slime was ammonium hydroxide, which is a known toxin. However, specifically w/ regard to Chicken McNuggets that's not how they make it any more. I think they changed a decade or more ago.
Here's what's in the bun and special sauce of a big mac. Preservatives, HFCS and other ingredients that are probably not good for you.
Big Mac Bun:
Ingredients: Enriched Flour (Bleached Wheat Flour, Malted Barley Flour, Niacin, Reduced Iron, Thiamin Mononitrate, Riboflavin, Folic Acid), Water, High Fructose
Corn Syrup and/or Sugar, Yeast, Soybean Oil and/or Canola Oil, Contains 2% or Less: Salt, Wheat Gluten, Calcium Sulfate, Calcium Carbonate, Ammonium Sulfate,
Ammonium Chloride, Dough Conditioners (May Contain One or More of: Sodium Stearoyl Lactylate, DATEM, Ascorbic Acid, Azodicarbonamide, Mono and
Diglycerides, Ethoxylated Monoglycerides, Monocalcium Phosphate, Enzymes, Guar Gum, Calcium Peroxide), Sorbic Acid (Preservative), Calcium Propionate and/or
Sodium Propionate (Preservatives), Soy Lecithin, Sesame Seed.
CONTAINS: WHEAT AND SOY LECITHIN.
Big Mac Sauce:
Ingredients: Soybean Oil, Pickle Relish (Diced Pickles, High Fructose Corn Syrup, Sugar, Vinegar, Corn Syrup, Salt, Calcium Chloride, Xanthan Gum, Potassium
Sorbate [Preservative], Spice Extractives, Polysorbate 80), Distilled Vinegar, Water, Egg Yolks, High Fructose Corn Syrup, Onion Powder, Mustard Seed, Salt,
Spices, Propylene Glycol Alginate, Sodium Benzoate (Preservative), Mustard Bran, Sugar, Garlic Powder, Vegetable Protein (Hydrolyzed Corn, Soy and Wheat),
Caramel Color, Extractives of Paprika, Soy Lecithin, Turmeric (Color), Calcium Disodium EDTA (Protect Flavor).
So I randomly looked up one of the ingredients that I couldn't pronounce:
In the UK, the Health and Safety Executive has identified azodicarbonamide as a respiratory sensitizer (a possible cause of asthma) in workplace settings and determined that containers of it should be labeled with "May cause sensitisation by inhalation." The World Health Organization has linked azodicarbonamide to "respiratory issues, allergies and asthma" for individuals at workplaces where azodicarbonamide is manufactured or handled in raw form. The available data are restricted to these occupational environments. Exposure of the general public to azodicarbonamide could not be evaluated because of the lack of available data