With lies & propaganda, of course!
This is a great article by Mariah Blake on the willful negligence that has led to the nearly 100% of the planet's population being exposed to the toxic and carcinogenic chemical known as "C8" (perfluorooctanoic acid, or PFOA).
It's also a great story of the tireless efforts of a handful of people - former employees, neighbors, farmers, etc- that worked to make sure that this whole thing was not swept under the rug by the chemical industry and DuPont.
Typical things that expose us to C8: stain resistant carpets, carpet cleaning liquids, Teflon cookware, microwave popcorn bags, Gore-Tex, floor wax, treated upholstery, clothing, and furniture, etc., food contact paper & wrappers, and dental floss.
Highlights include that DuPont knew about the health risks for nearly 50 years and did everything they could to cover it up and side-step their responsibilities to the public. While finally caught red-handed dumping their toxic waste, and ordered to pay the victims, communities, for clean up and even further research, etc. they still are doing everything possible to stall the actual restitution. One legal firm hired to administer funds to people has used $9 million while delivering $50,000 so far to victims, to give you an idea of how that's going.
Other standard Industry tricks, like hiring "regulatory strategists", lobbyists, public relations firms, and paying for narrowly focused scientific research meant to cast doubt on anyone or anything said against their "better living with chemicals" philosophy, and spin things to appear in their favor, as well as finally, creating a new subdivision within their corporate legal structure to hopefully distance themselves from the full legal, financial, and social consequences of their bad-actor behavior.
There's a movie in here, that I hope gets made so that more people are aware of this.
Oh, almost forgot the good news: 2015 marks the final year of the phase-out of C8. It has been replaced with the also largely exempt (grandfathered) or untested variants, like C6, C7, C5, etc.
Further reading:
https://en.wikipedia.org/wiki/Perfluorooctanoic_acid
http://www.foreffectivegov.org/blog/ten-years-after-toxic-chemical-settlement-dupont-failing-keep-its-promises
https://en.wikipedia.org/wiki/Weinberg_Group