Greenhouse gas pollution, through its contribution to global climate change, presents a significant threat to Americans health and to the environment upon which our economy and security depends.

I cannot shy away from controversy. I don't know if it's my Irish blood, but I love it.

EPA gets to set a standard for new. For the existing, EPA sets guidelines for what we think is appropriate, but then states develop plans that work for them, taking into consideration their specific energy mix.

Climate change is the greatest threat of our time.

Transparency is all about letting in and embracing new ideas, new technology and new approaches. No individual, entity or agency, no matter how smart, how old, or how experienced, can afford to stop learning.

There is no threshold level of fine particle pollution below which health risk reductions are not achieved by reduced exposure.

Greenhouse gas pollution, through its contribution to global climate change, presents a significant threat to Americans health and to the environment upon which our economy and security depends.