Leaking gas shook the leaves of the trees on Colchester Avenue the afternoon of Oct. 7 when construction workers hit an underground natural gas pipe.This incident – the second gas leak in two weeks — happened just two days after a power outage that left areas in and around UVM campus and the North End without power — bringing to question the integrity of Burlington’s infrastructure.  “[The Colchester] gas leak came down to poor judgment after the trench had already been dug, and one worker mistakenly assumed a pipe was where it wasn’t,” said Steve Goodkind, Director of Burlington Public Works.    Construction workers knew the Colchester excavation would be a difficult job with all the on-site utilities, Goodkind said.  “The gas pipe was just barely touching the outside of our trench wall the whole time.” “Most [gas leaks] probably aren’t dangerous, but we take precautions to treat them like they are,” Goodkind said.The Sept. 23rd gas leak at North Prospect and Loomis resulted from a lack of communication between Vermont Gas and Public Works.Dig Safe, an organization that provides the free service of marking underground utility lines prior to excavation, prompted utility companies to mark two dig-zones, but Burlington Gas had only marked one site.This incident resulted in the establishment of a Burlington Public Works policy that requires all underground utility companies to mark all dig zones before excavation.Vermont Gas has 700 miles of gas lines under Chittenden and Franklin counties, and “while the piping system is expanding, the number of line hits every year has decreased,”  said Jim Condos, public relations manager of Vermont Gas.Condos said that line hits are rare,  in part because of Dig Safe and good training.  Last year, Vermont Gas got 9000 calls from Dig Safe to mark their lines, and had only 16 hits to gas lines, making 2008 the year with the fewest incidents on record, Condos said.  Gas lines are safe and monitored Condos said. “We monitor our Vermont Gas systems 24/6/265 by our own gas control.”Burlington has an extensive underground network of cable, phone, electricity, gas and water/sewer lines. The most recent power outage on Oct. 5 affected approximately 5,000 Burlington Electric customers when a circuit breaker tripped at the East Avenue substation.There were three unscheduled power outages in Burlington in September alone, and the frequency of these events is “odd,” said Mary Sullivan, communications coordinator at the Burlington Electric Department.”[Burlington Electric] recently upgraded its equipment…and every year we reduce outages and become more efficient,” Sullivan said.  Within three or four years, Burlington will be using 100% renewable energy; a combination of wind, hydro, and solar, Sullivan said.  Sullivan explained that the whole city of Burlington’s energy usage has only risen one percent since 1989, demonstrating the effects of an energy conscious community.