In 1953, a paper developed for cigarette maker RJ Reynolds detailed possible cancer-causing agents in tobacco, but the document would remain hidden from public view for decades. In the interim, the industry told the public: “We don’t accept the idea that there are harmful agents in tobacco.”
https://www.theguardian.com/environment/2023/jun/07/pfas-3m-dupont-chemical-industry-health-toxic-study