MARCH 14, 2015
UNION TOWNSHIP, NEW JERSEY
A manhole explosion shut down several streets and prompted
businesses to be evacuated in Union Township Saturday morning. It happened during the St. Patrick’s Day
parade.
A stretch of road from the corner of Stuyvesant to Morris
avenues is closed in all directions, with additional closures along Morris Avenue.
PSEG crews and firefighters responded to the scene, and say
the situation is under control.
Officials say the cause of blast and underground fire is
most likely due to salt and water seeping into system. A number of businesses
were evacuated but were allowed to go back as of 2 p.m. No injuries were
reported.
The St. Patrick’s Day parade was delayed but still went on
as planned.
Source: pix11.com/nj12news.com
Manhole fires and/or explosions are often triggered by salt
or the melting mixture that leaks into the underground electrical system and
corrodes wires, which then ignite from electric sparks created by arcing.
A lot of times after it snows and the snow melts, salt that
is put down onto the sidewalk leaks into the system and can cause fires when it
hits the equipment.
What it does is it eats away the insulation that prevents
the different cables from touching each other.
Once the insulation is gone, you get this effect.
The flaming wiring can then release the dangerous gas, which
can leak into neighboring buildings as it builds up pressure below the
manhole. If sufficient methane gas is buildup
and there is a spark from an electric arcing, then it will cause it to explode.
Oftentimes, the gas that is buildup is coming from the
leaking natural gas piping. In New
Jersey, the gas infrastructure is very-very old in many places and it consists
of the old cast iron pipes. The useful
life of these cast iron pipes has long expired and essentially we are under a
Russian roulette situation waiting for the next explosion to happen should the
right conditions come together: sufficient leaking gas; oxygen; and a
spark. Then, boom.