Natural gas companies are facing the monumentally difficult and expensive task of replacing underground transmission lines in cities across the country, according to a recent article in the Wall Street Journal.

“After decades of neglect, replacing the huge backlog of old gas pipe is nearly impossible, says Mark McDonald, a pipeline-safety consultant and president of the New England Gas Workers Association. Digging up the aging lines and putting in new ones is so expensive and time consuming, there is not enough manpower—or materials—to get it done in short order,” The Journal wrote. “Everyone would like to have an instant solution to this problem, but there just isn't one,” Mr. McDonald told the newspaper.

More than 30,000 miles of aging cast-iron and wrought iron pipelines carrying explosive natural gas crisscross cities and towns around the country, according to the Journal. Big concentrations are centered in Boston and New York, and the defective lines are creating hazardous conditions. In New York, an old iron pipeline was implicated in a March 2014 blast that killed eight people. A gas leak from an undetermined source triggered an explosion last month in Boston that injured at least two people and sent about 10 others to the hospital.

“Regulators have long known that these pipes, which were installed starting in the 1830s, are far more dangerous than more-modern natural-gas lines made of steel or plastic. Iron lines are four times as likely as other kinds of pipe to be involved in an accident, according to federal data,” The Journal reported. “Regulators have made it easier for pipeline companies to pass along the costs of upgrades to customers. But utilities often don't want to lay out the millions of dollars of upfront funds and then wait years to get approval to recoup their spending.”

That fight has been playing out in New Jersey, where Public Service Electric & Gas Co. of Newark owns more than 4,000 miles of iron pipe, according to the article. “The Public Service Enterprise Group Inc. has been replacing about 60 miles worth each year, at a cost of $1.4 million a mile. At that rate, it would take roughly 60 years and $5.6 billion to complete the job,” The Journal wrote.

Replacing the outdated pipe more quickly would be extremely expensive. “You can’t replace them all at once and still have people able to afford to pay for heat and electricity,” says Stefanie Brand, director of the New Jersey Division of Rate Counsel.

But simply patching leaky pipes doesn't satisfy critics. “It’s been a recognized threat for years,” says Carl Weimer, executive director of watchdog group Pipeline Safety Trust in Bellingham, Wash. “We really need to speed up the replacement of these pipes.”

National Grid operates more old iron gas mains than any company in the U.S., some 5,500 miles of pipe across Massachusetts, New York and Rhode Island, according to the Journal. “It has been replacing an average of 140 miles of iron pipes a year, according to federal data. National Grid plans to pick up the pace so that it can replace most iron gas mains by 2040, although it could take another 10 years to finish the job in Boston and New York because of the density of the cities,” the article states.

Massachusetts lawmakers are mulling new rules that would require National Grid and other utilities to fix pipeline leaks faster, funded by customers, according to The Journal.

To read the Wall Street Journal article, click here.