An old trucker trick was to screw in a self tapping screw into a leak, a local trucker used to do this all the time, anyway when his tyre wouldn't hold air for long he decided to get it looked at. When the tyre tech went to pump air in the screws started to come out, just like a grenade.
He deflated the tyre and pulled out over 20 screws, he then told the trucker he wouldn't even try to repair that tyre, so the trucker took his tyre with him to another tyre shop.
The same tyre shop had a tyre tech blow his head off about 12 years ago when the locking ring slipped and came off, they changed the law and safety standards after that happened.