This is horrifying stuff.
This is probably a stupid question, but I am good at them. Can’t they turn off the gas from its source?
“This is probably a stupid question, but I am good at them. Can’t they turn off the gas from its source?”
Yes that is critical. The problem is that it sounds like a very large feed line has broken. The gas is already moving under ground. It will continue to disperse for some time even after the main line is shut off. The power company should cut all the power. That would eliminate many but not all of the ignition sources. The Gas simply won’t explode without an ignition source. Since modern appliances don’t have pilot lights then there are far more electrical ignition sources.
“Can’t they turn off the gas from its source?”
Yes they can, but you have what’s called line pack which is the volume of gas contained in the mains and services. The amount of gas depends on the size of the main, how many miles of main, pressure, etc.
For example a 50 mile section of a 42” transmission line @ 1000psi contains 200 million cubic feet of gas or enough to operate a stove for something like 2000 years.