The Nixon Administration set up the Environmental Protection Agency for an eponymous reason. Defining "pollutant" based solely on what’s in a substance without considering quantity or its effect is a thinly veiled attempt to skirt the agency's single objective. Just because carbon dioxide is a naturally occurring compound does not mean that releasing too much of it into the atmosphere is not a bad thing. Uranium is naturally occurring.  Should we let businesses be free to responsibly manage this too? Precedent matters.

The rest of the free world has collectively come to its senses on the need to responsibly manage our emissions, and now the United States insists on pouring as much as we possibly can into the atmosphere to the seriously toxic detriment of people everywhere, especially those least-equipped to guard against it. Think I'm being alarmist? Have you looked at the rise in heat-related deaths? Do you think the increase in natural disasters, and fatalities along with them, is just happenstance? Exactly what was predicted to play out is currently playing out: severe weather, drought, and disease (from Lyme Disease to Dutch Elm disease). Opponents of any attempt to regulate emissions complain that the cost on business is too high, but what about the costs on every single individual - from when they go to pay their insurance premiums to when they go to park at the beach (towns have to pay to rebuild after a hurricane)? To so patently ignore the true cost of doing business and reject good policy for the sake of profits borders on pathological.