Other carriers, Olsson adds, “aren't in it 100 percent”—meaning they will be more selective in the risks they assume and coverages they offer to this industry.

Stuart Anderson, CEO of Iron-Starr, a managing general underwriting agency representing Ironshore Insurance and the CV Starr Group of companies, says the fracking industry presents opportunity for an underwriter with the right knowledge. Iron-Starr has sent some of its underwriters to “shale school” and has met with lawyers and operators in order to grasp the risks of the business.

“There is significant exposure—from the risk of blowout to the risk of 50 trucks fueling around a pipeline at the same time,” says Anderson. “It has to be underwritten closely.”

The issue of experienced personnel has become a concern as fracking expands in the U.S., says Rick Gibbons, president of Zurich Global Energy.

“Millions of jobs are said to be created in the near future and that's good, but who are these people [on the project]?” Gibbons asks. “Are they trained?”

Gibbons also notes that “the supplies [required for fracking] are tremendous.”

Perhaps the biggest insurer concern around fracking is the uncertainty around legislation and potential lawsuits.

Olson observes that insurers are not so much “concerned with the process” of fracking, or the equipment or technology used; their concern centers around “public opinion—litigation and politics,” Olsson says.

“The difficulty is not that drillers are doing something new and dangerous, but that the activity has a higher profile with a more energized environmental lobby,” brokerage Willis says of fracking in a 2012 energy market report.

Indeed, a simple Internet search reveals dozens of litigation cases stemming from the practice and alleged resulting pollution and contamination of water sources.

And with such complex and unresolved issues at play, it is no stretch to come up with scenarios in which it is difficult to conclude whether certain coverage is applied or excluded. And it might be as difficult to predict which jurisdictions lean more favorably toward plaintiffs.

But as with any risk, it's all in the underwriting. The willingness of insurers to write the risks associated with fracking depends on whether those involved in the operations apply best practices to reduce the potential for accidents.

A final note on fracking: Shale gas drilling is not limited to the U.S., says Gibbons of Zurich. There was a recent “huge find” in China, for example, but the infrastructure to start operations doesn't yet exist, he adds.