If a lighting fixture is within the 20' range of a gasoline despencing area, mounted on a Bldg., as long as it's above 18" from grade level, am I OK to use the standard wiring methods? I was also wondering about an extention cord used in the area of Gas Tanks. Are there special cords for that use. If someone drills a hole through a building outside the range thats hazardous, but the extention cord is in the zone, what does a sparky with gas station experience think of that? The fixure would be surface mounted and fed from the back. Thanks

I use extension cords all the time within the class 1 zone. Maybe I'm wrong for using such but in 25 years I've never had a problem. I've also used listed equipment(portable pumps) with SO cord on them.

See 514.7 for wiring and equipment above Class 1 locations. It refers to 511.7, all fixed wiring above shall be in Metal raceways, etc. it goes on and lists all kinds of different conduits but no NM-b, interesting

SJT,
Just a cautionary note, here mate,
make sure that all of your connections are safe and are well tightened.
Petrol vapours are funny things, do not leave anything to chance!, it wouldn't be the first Service-Station, blown to bits, by faulty wiring connections.

I thought that the location extended twelve feet, not eighteen inches, above grade!
Of all the "haz-loc" fluids, gasoline has the widest range of flamability, due to the fact that it is a "soup" of everything from lighter fluid to wax. Even the use of cordless tools is questionable.
An extension cord, passing through a zone without connections, should be OK.
Going to an "extreme," as is typically done in refineries, you would use air-powered tools and non-sparking hand tools. That might be why the refining industry has the best safety record around.