By DANIEL GILBERT
ruptures, including one at an ExxonMobil pipeline that
caused a major oil spill in Arkansas last month, are raising
fresh questions about the safety of pipes made decades ago
using obsolete welding techniques.
Though the industry stopped making what is known as
low-frequency, electric-resistance welded pipe by about 1970,
it still accounts for more than a quarter of the 182,500 miles
of liquid fuel pipelines across the US, according to federal
data for 2011, the latest available.
The accidents come as federal regulators are examining
whether state-of-the-art inspection methods are capable of
detecting flaws in these old pipe seams. A US regulator has
commissioned a study of old, substandard pipe that could help
shape new rules.
In the Exxon rupture and another on a Chevron pipeline in
Utah last month that spilled 600 bbl of diesel near the Great
Salt Lake, segments of the pipes were made about 60 years ago
by bending metal sheets to form a tube, then heating the edges
with a low-frequency electric current to weld them lengthwise.
Such welds can leave defects in seams that make them vulnerable
to corrosion and cracks, risks that have been known for
The Chevron pipeline appeared to split along the welded
seam, according to federal regulators. A Chevron spokesman said
while the investigation continues, "Initial indications are
that the release may have been the result of a longitudinal
seam failure in the pipeline."
The Exxon pipeline gushed about 5,000 bbl of crude into a
residential neighborhood through a 22-foot, incision-like
"It clearly looks like a seam-type failure," Rick Kuprewicz,
a pipeline-safety consultant, said after seeing photographs of
the Exxon rupture.
Exxon spokesman Alan Jeffers said the company hasn't reached
any conclusions on the cause of the pipeline failure and is
awaiting a third-party review of the ruptured section, which
was removed on Monday.
"If we felt there was a problem we would have done something
else, but in hindsight clearly there was an issue," Mr. Jeffers
said of the company's safety tests.
It isn't clear from federal records how often obsolete welds
play a role in accidents. Of the 1,151 accidents on liquids
pipelines since 2010 reported to federal regulators, 78% don't
show what kind of weld was involved, and 85% don't show when
the pipe was manufactured, according to a Wall Street
Journal review of government data.
The Pipeline and Hazardous Materials Safety Administration says
most of the accidents involved very small spills, or weren't
related to pipe welds, so operators weren't required to furnish
detailed information about them.
But the number of pipeline accidents has been rising; the
364 accidents on liquids pipelines last year were the most
since 2008, but fewer than in 2002, according to federal
The threat of substandard welding "seems to be rearing its
ugly head again," said Carl Weimer, a pipeline-safety advocate
and executive director of nonprofit Pipeline Safety Trust. "The
issue is how well are companies mitigating for that risk?"
A spokesman for the Association of Oil Pipe Lines says old
pipe is safe as long as it is well-maintained, and that spills
are relatively rare.
Federal regulators have questioned the adequacy of
inspection methods that failed to reveal problems with these
pipes before major explosions, including a 2007 blast in
Mississippi that killed two people and injured seven.
The welds are such a concern that PHMSA, the pipeline
regulator, in 2011 commissioned a $4.2 million, multi-year
study of electric-welded pipes and how to prevent them from
failing while in use.
Battelle Memorial Institute, which is conducting the study,
has analyzed 280 cases in which electric-welded pipes failed
between 1950 and 2005, including 55 failures while the pipe was
in use. The nonprofit research group says the surest way to
identify a weld defect is to pump water through the pipe at
high pressure. Such tests are costly, requiring a company to
shut down the line, and in some cases apparently led to
failures when placed back in service, Battelle says.
The other chief testing method involves running a robotic
device through the interior of the pipe to detect any
anomalies. This device, commonly called a "smart pig," has at
times failed to catch flaws that later resulted in a
"Neither of them is foolproof," said Brian Leis, a
researcher leading Battelle's study. "Both are better than
Chevron last pressure-tested the pipeline that ruptured in
Utah in 1987, and inspected it internally in 2009. Exxon
conducted a pressure test on its Arkansas pipe in 2006,
according to regulators. It conducted an internal inspection in
2010 that didn't find any significant anomalies, and another
one in February, but hasn't received the results, regulators
By 1970, most pipe manufacturers began using a
high-frequency current to weld, which produced seams less prone
to fractures, according to a Battelle report submitted to
federal regulators in September.
Last July, a pipeline carrying gasoline in southeastern
Wisconsin split along an old electric-welded seam, spilling
about 1,000 barrels and prompting the evacuation of two
The operator, West Shore Pipeline, reported a second rupture
in August on an similarly antiquated seam. It pressure-tested
both pipelines more than a decade ago, and performed several
different internal inspections on them between 2009 and
"We are continuing to consistently re-evaluate our programs,
and consistently look to further test our lines to maintain
them safely and operate them safely," said Patrick D. Hodgins,
a spokesman for Buckeye Partners, which controls West Shore
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