* U.S. agency found prior problems at Exxon pipeline
* Exxon had been faulted for leaking valves on pipeline
* U.S. govt will have to approve restart of pipeline
By Tom Doggett
WASHINGTON, July 4 The U.S. pipeline safety
regulator said on Monday it is investigating the leak at Exxon
Mobil's (XOM.N) Silvertip Pipeline in Montana that spilled
about 1,000 barrels of oil and that it had warned the company
before about problems with the pipeline.
"Inspectors are on site and have initiated an investigation
into the cause of failure," said a spokeswoman with the
Transportation Department's Pipeline and Hazardous Materials
The spill, which Exxon Mobil found early Saturday near
Billings, Montana, released up to 1,000 barrels of oil, or
42,000 gallons, into the Yellowstone River.
Though the Exxon pipeline is relatively small and does not
cross state lines, the agency still regulates it.
PHMSA would have to approve a restart of the pipeline, said
the spokeswoman, who added it was unclear when that might
Depending on what inspectors find during their
investigation, the agency may issue a citation or a notice
requiring the company to take specific correction action, the
After inspecting the pipeline in July 2009, PHMSA issued a
warning letter to Exxon a year later about oil leaking from
some of the valves on the pipeline.
The agency said the valves did not have a means for clearly
indicating whether they were opened or closed. As a result
"there was fresh crude oil on the soil immediately adjacent to
the valves," PHMSA said in its warning letter.
It also faulted Exxon for not following up in a timely
manner on atmospheric corrosion issues that were identified
during three years of corrosion surveys on the pipeline.
In addition, the agency said Exxon did not have an updated
map or drawings of the pipeline to include information on the
pipe's reconditioning near Rock Creek from 1999 to 2001. The
agency said a mainline valve shown on the map appeared to no
"Exxon Mobil must update the alignment of the Silvertip
Pipeline to ensure that the drawings accurately reflect the
pipeline location and the facilities installed," the agency
Exxon resolved all the concerns raised by the agency and no
fine was issued.