What is Flint Hills and what health effects are associated with it? How does these EPA handle situations?

Honestly, I'm confused over this. I'm study environmental problems, and I have been tasked to solve this question over water pollution. I'm confused over what exactly is Flint Hills - a company or mountains - and what health effects are associated with it. What is Flint Hills and what health effects are associated with it? How does the EPA handle situations like Flint Hill?