Real De Tayopa, you say: "I was hit with cyanaide poisoning. As a result I can now smell an open container or area where cyanaide has been used up to 30 + metres." Great, you have a keen sense to sniff out a particular compound. Therefore, this keen sense IS within the realms of human acheivability. Ie.: it is within the realms of normal, since you have attained to it.
But let's say that I claimed to you, that I could talk to the dead, see into the future, cast spells, etc... If I tried to tell you those things were merely naturally attainable, scientifically explainable, etc... You would tell me "Nope, it is occult. Those are not "natural things" at all.
I mean c'mon Real, pick ANYTHING you would truly call superstition, occult, etc... Now, get that practice in your mind. Got it there? Ok, now, go apply all your same defenses about dowsing, and see how they too can also be used to prop up the very practices that even you would call occult. How can you deny those practioners the same lines that you use?
No I'm not saying you don't sincerely believe that it's natural and scientific. I'm not saying you're on par with the trouble-maker goth kid who wants to get into spooky stuff. And yeah, spooky stuff can work! Weird things go on in this world.
There's no way a brass rod finding a coin a mile away can be supported from science or natural abilities (ala, like heightened smell). In the same way that other spiritual things are also not naturally occuring or scientific. They exceed and go beyond science (whether known or unknown science) and go beyond natural ability.