Geez Marn, that bites! I've never heard of anything like that stuff you are describing, nor do I have a clue of anyone willing to weld on a tank that has gas fumes in it. Sorry bro.
I have heard and often used "it's not carnage, it's an upgrade opportunity", but you are the first person I know that has turned your opportunity to upgrade into a carnage situation. Let me know if you need an extra set of hands to help you out.