The economic and environmental costs and benefits of natural gas have been widely debated though most contend that gas is less environmentally damaging than petroleum. Also, quite a large amount is available right here in the US. However, as with most extractive industries environmental damage results from access. Recently a Congressional investigation reported that part of the extraction process called "fracking" has entailed the injection of tens of millions of gallons of diesel fuel into the ground, a process that could be in violation of the Safe Drinking Water Act. The EPA is responding to the accusations with an investigation of its own.
If natural gas really is a step in the right direction, as it appears to be, then hopefully an appropriate set of regulations can be established to minimize its environmental impact. If we're going to use it because it's cleaner, let's be sure we keep it that way!