Years ago my parents had a Weber gas kettle. One Sunday we sent our brother out to the garage to light up the grill. Things were normal for a while until about 20 30 min went by and someone finally noticed Ray was missing. Looked all over the house couldn't find him, finally we went to the garage and found him sitting on the floor front of his hair and eyebrows singed off, face red and eyes spinning around. Lid from the grill laying upside down on the floor.
When we finally got him "around" we're like "what happened?" He said "I'm never lighting another grill again". He followed our directions EXCEPT he did not leave the lid off. So there he was, gas going in that thing lid on and he's down low trying to push that stupid igniter up and click it. Of course his face was right next to the kettle. He FINALLY got the thing pushed up it clicked and BOOM the lid blew straight up, a fireball came out, singed his face and blew him against the solid brick wall, he hit his head and it knocked him silly. Took him a long time to live that down LOL
Moral here? Open the lid!