Thanks for the picture. From this, it looks like gasoline has already been obtained. You can get gas just by touching it. If you check "Items" or "Key Items" you should find it in one of them.
If not, save anywhere and restart the game. If it is a bug, there may be gasoline in the location shown in the picture.
If not, you probably already gave it to the person who should have.
And one more thing. Can you take a screenshot and tell us what needs to be done now in the story?
You can find it in the menu under "Objective".