The fracking boom in America's wide open spaces is causing a challenge for the crews of intercontinental ballistic missile sites, according to the general in charge of the Air Force Global Strike Command.

Over the past decade, the natural gas extraction business, including its influx of drilling crews and truck traffic, has spread across the same states where the 20th Air Force maintains its nuclear missile sites.

"It is a contested area of responsibility. It is contested by fracking," Gen. Robin Rand said.

Air Force missile operators and maintainers at facilities such as Malmstrom Air Force base in Montana drive hours for shifts at the remote sites eight to 10 times per month, he said.

"We're in the same area [as fracking operations], so these are out in the middle of nowhere, if you will, on some narrow roads. So it's just a challenge," Rand said.

The 20th Air Force has territory that covers more than 33,000 square miles in Colorado, Nebraska, Wyoming, Montana and North Dakota.

The process of hydraulically fracturing rock and extracting oil and gas has revolutionized U.S. energy production in recent years. It has created booms and busts of industrial and business activity in areas across the country.

"It's just an encroachment challenge, and we've got to be aware of it," Rand told a breakfast meeting on Capitol Hill. "It requires a little more scrutiny and time … There's no safety issues, it's just that it requires more attention to detail than probably ever before."