I’ve learned when something sounds too good to be true, it often is.

We should not, as a nation, rely too heavily on natural gas for our energy future until we have a better understanding of the full impact it has on our environment. While gas may be cleaner to burn than coal, the truer test of an energy source’s environmental impact is to look at it from start to finish, including exploration, transportation and end use. And hyrdrofracking carries significant environmental risks, including dirtying our drinking water and making our planet more susceptible to earthquakes.

The U.S. Geological Survey reported in April that the number of seismic events in our country’s midsection has risen from about 21 in the 1990s to 50 in 2009, 87 in 2010 and 134 in 2011. The scientists concluded that fracking - when water, sand and chemicals are injected into the Earth’s deep shale formations to break up rock and extract the natural gas – was the most likely cause.

While these earthquakes are minor now, the more we allow corporate America to drill into our planet without proper regulation, the greater the risks grow. Already, our nation’s capitol has seen the long-term effects even a small earthquake can have to homes, buildings and monuments.

Hydrofracking produces radioactive wastewater that can be discharged into our rivers and often finds its way into our drinking water. This wastewater can be hundreds, or even thousands of times above the maximum federal standards for drinking water.

As Thomas Friedman recently noted, the carbon advantage that natural gas holds over coal can be undermined by leakage from pipelines and wellheads of methane, the primary component of natural gas, which can be more dangerous than the carbon dioxide given off by coal. Drilling companies have repeatedly been exempted from federal safety standards designed to protect water and air from hazardous chemicals. Already, 12 states have reported health problems linked to hydrofracking, including air and water contamination.

There is also the metaphorical earthquake we have seen natural gas exploration cause, with neighborhoods uprooted by the onslaught of frackers into their world. Oil companies have rushed into communities, promising riches for the right to drill, and left economic and environmental destruction in their wake. Water is contaminated, livestock and crops are damaged and homeowners are left unable to sell or refinance because of leases they’ve signed with natural gas drillers.

The Obama Administration has started to put regulations in place to protect our environment, but have faced pressure from those both inside and outside the industry who oppose any rule that might slow down the pace of drilling.

Given the myriad of concerns around natural gas, Americans should demand a policy structure that encourages fracking only with full proof that it can be done safely and under strict federal guidelines. Our government should understand the full scope of natural gas exploration’s environmental and human health impacts long before we ever declare it the fuel of a clean energy future.

And even if the reality of the natural gas revolution one day matches the high-pitched rhetoric, we must ensure that its development occurs alongside other energy exploration. The incessant cry for more natural gas comes at the expense of other potential sources and is likely to limit innovation, making our country dependent on an energy source that carries great risk.

The fact remains that all fuels have their advantages and downsides. U.S. energy policy should reflect that.

There is no doubt that natural gas can play a role in loosening America’s dependence on foreign oil. But it’s not the only option, and it is incumbent on our government, not the oil and gas industry, to determine which is most likely to provide us with the fuel we need for the future, while maintaining a healthy and safe planet for our next generations.

Dellums is a former member of the U.S. House of Representatives and mayor of Oakland, California .