In comments to reporters at a Google event in Boca Raton, Fla., on Monday, former Vice President Joe Biden broke with long-standing campaign tradition by calling for a ban on the use of the “fracking” technique to extract crude oil from shale formations.
Mr. Biden also said Congress should increase taxes on big corporations as a way to reduce the federal budget deficit, with the money used to rebuild infrastructure.
He gave no specific proposals on either issue.
But such a major address by the potential Democratic presidential candidate would have been unthinkable just a few months ago, when many Democrats were eager to stress a message of expanding the middle class and defending Social Security, Medicare and the nation’s commitment to military spending.
Now, some key Democrats are having second thoughts. Senator Bernie Sanders of Vermont, a leading liberal in the Senate, has questioned the potential for fracking to be curtailed, even without regulations on land leases. Senator Elizabeth Warren of Massachusetts has also shied away from embracing fracking, despite having served on panels that have recommended limited use of the technique.
At least two industry representatives in private discussions at a Friday night fundraiser for Mr. Biden cited his frack remarks.
“It puts him on more of a different footing with the left,” said one executive, who asked not to be identified to protect business relationships. “Now is not the time to be talking about fracking and what’s wrong with the industry.”
A spokesman for Mr. Biden, Alex Conant, said the reaction was “hypocritical and baffling.”
“The fact is that the oil and gas industry has already reduced the environmental footprint of production and are working to find innovative solutions,” Mr. Conant said. “No one in this country has more to gain or lose by choosing a catastrophic climate solution than a potential presidential candidate.”
The industry also assailed Mr. Biden for detailing additional government spending and taxing increases during an economic recovery that has not helped hundreds of thousands of Americans looking for work.