are there for a good reason. If you do, in fact, keep a lighter lit for more than 30 seconds, the flame will suck back into the lighter, making a “Zoop” sound. This will cause the lighter, with all of the remaining fuel left in it to violently explode, and can result in a serious injury. I do not encourage anybody to try this.
Zoop a lighter
The warning label on the sides of disposable butane lighters that say “Do not keep lit for over 30 seconds”
“Hey, look out dude! The lighters gonna Zoop on you!”