I work in the industry. You'd be surprised how often this type of thing happens when contractors hit a line that was not marked or marked properly. Lots of times a backhoe contractor for another utility or project will say "I can see the pipeline markers; I don't need to do a one-call and have to wait 48-hours for someone to mark it." Or if they hit it and it doesn't leak immediately, they cover the dent and go on their way. However, the coating has been damaged and the possibility that a future leak will occur due to corrosion is great. Also, contractors will put a guy on a backhoe that can't speak English well and hasn't been safety trained. When you have buried utilities, you make sure you hand dig anytime you're crossing buried lines.
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The NG release last Thursday was shooting gas 100' up with a huge gas gas cloud much higher drifting South.
CD, you took the words right out of my mouth. That exact scenario happened about 2 miles down the road from me several months ago. The only difference is, the construction guys knew they hit the line, called the gas company who said nothing registered on their equipment. About 2 hrs later “BOOM!”. My parents were able to see the fireball about 60 miles from the blast site.