The free market has never existed on a wide scale, so no company currently has to survive in a free market. It is a thought experiment and in practice regulated markets are far superior because the market is a pretty bad governor for society. Further, to have a free market you need perfect transparency, a state which is not realistically possible to begin with but if it were possible would only be achieved through regulation, such as disclosure requirements.
In that free market, by the way, companies absolutely will poison the air and water, in large part because people do not make purchase decisions based on downstream externalities. Even if they did, they won't be able to prove the company poisoned the river and the company won't be breaking any laws so a lot of people will simply allow it to continue. Now if the products themselves were poisonous, it's possible, but historically this just led to merchants moving from town to town to poison new people who hadn't heard of them.
>The reason companies do nefarious things is government interference in markets, insulating companies from competition.
This is so ridiculous I am not sure you're serious now. Are you just trolling?