North America. Creosote was the standard traditional preservative for all kinds of outdoor wood applications,
not only railroad ties but fenceposts, telephone poles, etc, pretty much everywhere, until is was replaced mainly by pentachlorophenol and chromated copper arsenate (both are even more hazardous). All of those are now banned.
In recent years the smoke from our massive brush fires has been especially noxious due to all the naturally occurring creosote involved. There are no doubt analogous forms of vegetation involved in the recent big fires around the Med. in Europe. Vaughn, being a forester, would understand. Maybe mustard goes well with grilled ground squirrel or badger, or something like that.
Ironically, my horse liked to chew creosote treated posts while flirting with his girlfriend mare across the fence on the neighbor's property, likewise chewing from her side. It ended up as wooden balls suspended from the barbed wire (and a big repair chore for me). The creosote would have been thoroughly outgassed - some of those posts were over a hundred years old. Some of the remaining cedar posts were ruined by woodpeckers.