Energy experts say the boom in Marcellus Shale natural gas production will slow this year but not because of a lack of supply. 

The slowdown is happening because drillers are waiting for pipelines to expand, new markets to develop and wholesale prices to rise.

The president of the industry group Marcellus Shale Coalition says hiring has tapered off and most companies are in a holding pattern.

Colorado company Bentek, which analyzes energy trends, estimates that total Marcellus production rose to about 2.8 trillion cubic feet in 2012, about double the previous year. That's about 10 percent of the nation's natural gas output.

About 75 percent of the Marcellus production came from Pennsylvania, and most of the rest is from West Virginia.

The Marcellus formation also lies beneath New York and Ohio.