[2015] McDonald's french fries found to contain Silly Putty ingredient and petroleum chemical   Imahara went directly to the fast food chain's processing plant in the potato-loving state, where he thankfully learned that the fries' first ingredient are indeed spuds. However, the ingredients that followed are disturbing to say the least. Included on the list of 19 items are dimethylpolysiloxane, a form of silicone found in Silly Putty, tertiary butylhydroquinone (TBHQ), a petrol-based chemical, and hydrogenated soybean oil, which is a manufactured form of trans fat....According to Vani Hari, more commonly known as the "Food Babe" who helped bring Subway's bread ingredients into the spotlight in 2014 for their use of a substance that's also used in yoga mats, dimethylpolysiloxane should be avoided. The McDonald's french fry ingredient is the same as what's found in aquarium tank sealants, mold release agents and hair conditioners. In some cases, she explains that it even contains formaldehyde, a highly toxic chemical associated with brain damage, cancer, allergies and auto-immune disorders