A surge in U.S. natural gas development has spurred $226 billion in spending plans on pipelines, storage, processing facilities and power plants, most slated for the next five years, according to Industrial Info Resources, a market-intelligence provider in Sugar Land, Texas, Bloomberg reported.

U.S. natural gas production will expand to a record this year, and oil output swelled in July to its highest point since 1999, Bloomberg said.

Citigroup Inc. estimated in a March report that a “reindustrialization” of America could add as many as 3.6 million jobs by 2020 and increase the gross domestic product by as much as 3 percent.

So far, the economic benefits have been confined to states such as Louisiana, Texas and North Dakota, while the national jobless rate has stayed above 8 percent for 42 straight months in the wake of the worst recession in seven decades.

“It is definitely a positive for the economy, but one can overstate how much of a positive,” said Michael Feroli, chief U.S. economist for JPMorgan Chase & Co.

Oil and gas production account for about 1 percent of gross domestic product, and will have a limited impact on the country’s unemployment, he said.

Even so, there are signs the economic gains have begun to expand beyond the oil and gas fields and that the promise of abundant, low-cost fuels will give a competitive edge to industries from steel, aluminum and automobiles to fertilizers and chemicals, Bloomberg said.

The expansion of fossil-fuel production — coupled with a weak economy and increased energy efficiency — has helped the United States pare its crude oil imports by 17 percent since the 2005 peak, according to U.S. Energy Department data.

Imports in 2011 accounted for 45 percent of U.S. consumption of crude and refined products. The Energy Department predicts the share will fall to 39 percent next year, which would be the first time since 1991 that imports dropped below 40 percent of demand.