I actually seen photos of those in action: during 70s, my parents had natural gas well in their backyard and one day it did catch the fire. Fire fighters waited

I actually seen photos of those in action: during 70s, my parents had natural gas well in their backyard and one day it did catch the fire. Fire fighters waited for week or two and hoped the gas will deplete itself, after that they bring those machines which blow out the fire. So those machines are probably few decades older than stated in article.