more than 2,800 gas line accidents have been recorded since 1990 a third causing death and significant injury. by law, pipeline operators are required to conduct leak surveys, one of the more common ways to ensure safety. shepard: there was a leak detection survey of some kind, near the shiite of the sight of the latest? reporter: yes, we went and saw the trucks dispatched throughout the neighbors equipped with methane detection funnel cones in front of the truck, and the system gets a hit, operators bust out their portable hand held leak detectors to take a closer look, a common practice, and experts say age is only one factor in determining the integrity of the pipeline, and they also look at the leak history of the pipe, and the composition, and a lot more questions coming coming toe hearing tomorrow morning when it continues. shepard: the norad reports
beat now. martha: i think so, too. bill: the foot work. martha: he can move. bill: now underground time bombs, possibly ticking under your home, recent pipeline explosions like this one, that killed 8 people in san bruno, california, what a morning that was. and now, prompting the feds to look into our country s aging gas lines and lara ingle is live on that in our newsroom now, good morning, lara. reporter: the last time the national transportation safety board held a public hearing on pipeline safety was in november of 2000 and just last hour, the ntsb kicked off the rare three-day hearing, to dig deeper into the root cause of the san bruno last and, look at ways the pipeline operators can improve safety before another incident happens. philadelphia, pennsylvania. san bruno, california. and most recently, allentown, pennsylvania. the scenes of horrific gas line explosions. that left neighborhoods in ruin and 14 people dead.
we are not doing near as good a job as we should be able to do. reporter: more than 2800 significant gas pipeline accidents have been recorded across the country, since 1990. a third of them, causing death and significant injuries. we have an aging infrastructure, across the country. and particularly the eastern half of the country, and, pennsylvania. reporter: there are more than 210 natural gas pipeline systems, made of cast iron, steel and plastic, which snake underground throughout the lower 48 states and 21,000 miles of it, through heavily populated areas. a dangerous combination say watchdog groups. cast iron pipes fail and they envisioned they d be replaced over time and here we are more than a century later and we have them in the ground and they are sort of a ticking time box. reporter: by law, private and public pipeline operators are required to conduct leak surveys which continue to be the most important ways to ensure the
age is only one factor in determining the integrity of a pipeline. other factors include the leak history of the pipe, the composition, population density around the pipe, the geography, the road traffic patterns. reporter: by law private and public pipeline operators are required to conduct leak surveys which continues to be one of the most important ways to insure the safety of the lines. our fox team went aeu on a ride-along in allentown, paepbz to check out how it s tkofpblt you can see the crews use gas detection sniffers on the outside of trucks, rubber cones that can pick up methane gas and they get out to check with hand-held devices as well. they say they spend up to $20 million per year upgrading and replacing gas maines and they are vigilant about conducting leak detection surveys, and in fact did one two days before the allentown
commission was urged to quickly inform all pipeline operators in california about the ntsb report. in its investigation, the ntsb uncovered some alarming findings and they include the ruptured pipe included welded seams instead of seamless steel construction. some seams were welded only on the outside. others were welded both on the inside and outside. the board believes that seamless steel pipes might be stronger than ones that are welded. the ntsb is expected to issue its final report later this year. the ambulance that transported the body of president john f. kennedy is up for auction. the details after this quick break.