there is a strange smell of oil/petrol in house!!?? what could it be?

[snowisgone]

Guy came and unblocked air lock in hotwater tank smell coming from outside even washing smells of it a bit don't think it is the house!! what could it be?

no idea what the smell could be...check if my dh is hiding in a cupboard!!!!!
He comes home and reaks of oil, white spirits, and general yuckness.