BHT (butylated hydroxytoluene) is a synthetic antioxidant used in various products, including some cosmetics, sunscreen, moisturizers, body washes, deodorants, fragrances, shampoos, hair and acne treatments, soaps, hair sprays, and in the packages of croutons.
It can cause allergic skin reactions, been labeled a possible carcinogen, and a endocrine/hormonal discruptor. BHT exposure in animal studies caused liver, thyroid, and kidney problems. It can accumulate in aquatic life as well.
Solution? Avoid products containing BHT.
Still want croutons? Take a look at this article for a few healthier strategies.