Fragile pipelines pose increasing risk in gas-hungry US

New York

THE kind of dramatic scenes that played out in suburban Massachusetts last month following a series of explosions and fires may serve as a warning of what lies ahead for the United States, where an increasing reliance on natural gas is running up against ageing infrastructure.

While there's no firm conclusion about what caused the series of deadly blasts on Sept 14, a preliminary National Transportation Safety Board report on the incident released last week says it was linked to work being carried out to replace old pipes.

And across the US there's an awful lot of old pipes: in all, the country has about 80,000 miles of unprotected bare steel and cast or wrought-iron natural gas pipes - enough to wrap around the Earth three times - much of which dates back to the early 1900s.

"Ageing infrastructure is clearly an issue in the US, especially on the East Coast where they have a lot of old cast iron pipes that are well known to fail," said Carl Weimer, the executive director of the Pipeline Safety Trust in Bellingham, Washington.

While those lines represent just 3.6 per cent of all the pipes that deliver gas to consumers nationally, they pose the highest risk and account for 41 per cent of all fatalities, according to the Pipeline and Hazardous Materials Safety Administration.

PHMSA, as the regulator is also called, has urged operators to accelerate plans to replace the oldest lines because decades of wear and degradation has made them more brittle and prone to leaks or ruptures from ground movement.

Exposure to rain and freezing temperatures is also a problem (modern gas lines installed in towns and cities are made of plastic, which is corrosion-resistant and less brittle, or from protected steel that won't rust as easily).

To be sure, the natural gas industry has come a long way technologically since it began about 200 years, with improvements such as new materials and inspection tools, said Christina Sames, vice-president of operations and engineering with the American Gas Association, a Washington-based industry group.

Utilities continue to spend billions of dollars to replace old lines. In Ohio, for example, the Public Utilities Commission oversees programmes undertaken by utilities including Duke Energy Corp.

But while those lines are being ripped out and replaced, there's a huge build-out of new pipelines, driven by the shale-gas boom. And that's prompted concerns that the regulatory environment hasn't kept pace.

Despite the inherent dangers of routing natural gas around the country above and below ground, its use has grown in recent years. It accounted for 29 per cent of the US energy mix in 2017, and that share is set to expand thanks to the exploitation of the massive reserves in shale-rock formations around the country through hydraulic fracturing, or fracking.

That shale-gas boom has slashed the cost of electricity and is set to turn the country into the world's third-largest shipper of the heating and power-plant fuel within the next two years. It's also precipitated a huge build-out of pipelines. Since 2000, the Federal Regulatory Commission has authorised almost 18,000 miles of interstate gas transmission pipelines totalling more than 159 billion cubic feet per day of transportation capacity.

US oil and gas pipeline-related deaths jumped to the highest level in seven years in 2017. The 20 fatalities were the most since 2010, when a gas pipeline explosion in San Bruno, California, killed eight.

The government figures include both large pipelines that crisscross the countryside as well as smaller lines serving residences. But as data from PHMSA makes clear, it's the older pipes made of of cast-iron that are disproportionately deadly.

Similar incidents can be found on a grim list on the agency's website. In January, for example, four people were injured in a Brooklyn fire that followed damage to a cast-iron gas pipe that the regulator says appeared to be be caused by "frost heave", where the ground swells upward due to freezing conditions.

There were five deaths in 2011 after an explosion and fire in Allentown, Pennsylvania, where a preliminary investigation found a crack in a cast-iron main installed in 1928.

Perhaps ironically, the blasts and fires that last month ripped thorough several towns in the Merrimack Valley, north of Boston, happened as work was under way to replace ageing gas pipes operated by NiSource Inc's Columbia Gas of Massachusetts unit.

According to the NTSB report, crews contracted by Columbia Gas were replacing a cast-iron distribution main with a plastic one. BLOOMBERG