Underground Gas Leak Creates Explosive Conditions in Portland, MaineJul 28th, 2011 | By Mark | Category: Lead Articles, Natural Gas Leaks
A natural gas leak in Portland, Maine created potentially explosive conditions along a five block stretch beneath one of the city’s major commercial thoroughfares early Sunday morning.
According to an incident report obtained by NaturalGasWatch.org, a pedestrian flagged a passing police to report the smell of natural gas near the intersection of Cumberland and Washington Avenues shortly after 4:30 a.m. on the morning of Sunday, July 24. The officer called in the Portland Fire Department, who took gas readings from the manholes near the intersection.
The initial reading indicated a natural gas presence approaching 60 percent in the manhole — well above the explosive level. PFD personnel called in Unitil, the company that owns and operates the natural gas pipeline infrastructure.
From the PFD incident report No. 01-2011-0008537-000:
We went up to the intersection of Washington Ave. and Congress and in the telephone manhole we had levels at or above the explosive level (we left the cover in place). In time we found from Smith and Congress all the way to almost (the) Munjoy Hill Fire Station (all on Congress St.) at least the explosive level of Natural Gas in the telephone manholes.
The PFD incident report states only that Unitil personnel suggested that the fire department ventilate the manhole covers; it does not indicate whether the utility affected repairs to the pipeline.
Neither Unitil Vice President for Communications and Public Affairs Carol Valianti or Media Relations Manager Alec O’Meara responded to inquiries from NaturalGasWatch.org.
Documents obtained from the Maine Public Utilities Commission indicate that Unitil operates 62.49 miles of cast-iron natural gas mains beneath streets and byways throughout southern Maine, with a significant amount of those lines running beneath Portland streets.
Aging cast-iron natural gas pipelines — many of which date back to the 1940′s and before — are particularly susceptible to leaks brought about by corrosion, environmental damage and other natural causes.