Unlike its House counterpart, a climate change bill introduced in the Senate this week would not prevent the Environmental Protection Agency from writing greenhouse gas emissions regulations.

The House bill, which would create a cap-and-trade system for controlling emissions, would rob EPA of some of its authority under the Clean Air Act. EPA would not be allowed to set and enforce greenhouse gas emissions limits in the way it does for other pollutants like smog and soot.

But the Senate bill, introduced Wednesday by Sens. Barbara Boxer (D-CA) and John Kerry (D-MA), includes no such provision.

Most players in the climate change policy debate prefer congressional action to regulation. The business community is terrified that EPA will finalize regulations under the Clean Air Act – a fear that has led some companies to lend their support to cap-and-trade legislation. Although many major environmental groups also support cap-and-trade, they do not believe EPA’s authority should be taken away. They think cap-and-trade and regulation can coexist.

Senate Republicans are already complaining that coexistence would be “totally unworkable.” The circumstances may turn EPA’s regulatory authority into a bargaining chip, according to E&E Daily (subscription). Kerry indicated he may be willing to insert a provision preempting the EPA in exchange for broader support.

It’s a tantalizing offer for businesses and the lawmakers they influence. Heavy emitters don’t want to have to go to EPA for permits, they would rather buy, sell, and trade emissions credits.

And EPA has been moving aggressively on climate change regulation. Wednesday, the agency unveiled a proposed rule that would cap greenhouse gas emissions at major industrial facilities. Absent a congressional override, big polluters will be facing strict emissions limits in just a few years.

Environmentalists will continue to advocate for preserving EPA authority. Even if cap-and-trade is the dominant system, Clean Air Act regulation could serve as a backstop. If facilities find a way to game the system, or one facility gobbles up too many emissions credits, the option for regulation is still there.

The Senate is not likely to do much with this bill in 2009, so Senators will have plenty of time to haggle over this and other provisions.

Image by Flickr user kandyjaxx, used under a Creative Commons license.