Is promethium essentially oil? The warammer wiki states it essentially is petroleum based but each planet's version is unique. I was wondering since the only place I have seen it mentioned specifically was in a Cain book that took place on an ice world.

I am asking as I am currently toyig around with an adventure the gist of which is promethium becomes warp tainted and when burned releases mutagenic fumes.

I've always thought of it as similar to oil. It seems that it can be used in flamethrowers without much processing so it might be a bit different in that regard, but I still think the oil comparison is good.

Also, that's quite an interesting idea for a plot point! Nice one.

I think it's basically gasoline (petrol if I have my British English right) as it's used both as a fuel for vehicles and for flame throwers.

Warp tainted promethium sounds like an interesting plot concept.

Luckily, Promethium in Wh40k has nothing to do with real life Promethium.

Promethium as it appears in the game would be something along the lines of 'Napalm B' I guess, with the40k equivalent to gasoline mixed in there, but not the pure stuff. Most flamethrowers used to utilize a flammable liquid with a thickener thrown into the mix, though newer ones may also rely on gaseous ammunition entirely.

In addition, it seems to be used as kind of "rocket fuel" as well, since Promethium tanks were mentioned (as far as I remember) at a lot of facilites for space crafts (last mentioned in the RT Kitt Adventure "Whispers on the Storm" where it is mentioned that some council initially feared that a taken promethium refinery would be used to refuel enemy ships).

But thinking of it as "petro chemical" seems fine. As far as I know, the early Napalm version (what Promethium is most prominent for in the 40K-Wargames) was gellied gasoline. So, it seem alright to that "Promethium" is based as fuel for vehicles, shuttle rockets and flame weapons alike (depending on the great/method of refinery).

The best description I can think of is: Space Petrol.

Like many things in the Imperium the term appears to be used for an awful lot of substances which fufil the description of "Flamable liquid which releases large amounts of energy when burned". The Munitorium probably have several specifications for the substance and possibly grades of promethium depending on the ignition temperature, energy released, waste products, volatility and viscosity.

I certainly remember the Ciaphas Cain novels mentioning promethium fumes from Imperial heavy armour so I see no problem with the adventure premise.

As I understand it, Edith's hit the nail on the head. It's space petrol.

Logically, if there are many planets that have the same processes that create petrol on earth (geology and biology) then petrol must be quite common across the galaxy. I'm not a scientist (to put it mildly) but my understanding is that petrol is effectively ancient biological matter (usually plant life) that has decayed, broken down, and then been compressed by geological processes for thousands or millions of years.

So there are probably loads of planets with massive petroleum deposits. All of the worlds will produce slight variations in the exact chemical composition, but it'll be broadly the same stuff, one would imagine. Edith's suggestion that the term "Promethium" is effectively a standard that local fuels are expected to be graded to as much as it is a general term for fuel is a very sensible one.

Even in an Imperium with plasma reactors and high energy power cells you can imagine there's a place for promethium. Plasma power seems somewhat unstable (probably because of a lack of knowledge about how it should be maintained rather than any inherent flaw in the technology), and there won't always be technomagi senior enough locally to maintain such plants. Promethium can be mined and used locally on frontier worlds using relatively low technology, and it can be used to power a wide variety of mechanisms.

http://wh40k.lexicanum.com/wiki/Promethium

Basically, any form of fuel is generally called Promethium in 40k. This could be natural/liquid gas, oil-based, literally anything.

At a guess its the laymans term for Hydrocarbons in general

I like the idea of Promethium being more-or-less the same substance used for fuel of many varieties as well as flamer ammunition (and God-Emperor knows what other uses it has), as it keeps up well with the idea of the 'standardised' Imperium, in the same way Lasguns are the primary armament of the Imperial Guard - anyone can pick it up, use it with minimal knowledge, and it will likely do the job anywhere or anytime.

If every planet in existence is able to burn promethium, you don't have the hassle of trying to send certain shipments to certain places and the like; you can just say "X STC-units to this planet, Y units to this other one." If that same promethium can be used for a bunch of different machines or even weapons, even better.

The Hobo Hunter said:

Never mind that, this being the case, somewhere, someone's using Imperial Napalm in their table lamp. :-D

Just one of the many reasons I love this setting.

My players ran out of fuel in their vehicle (a Rhino variant I created named "The Calixian Tithe Collector" - check out the details on Dark Reign (selfless plug....)) whilst transporting a known heretic across the storm and snow wracked forests of Sepheris Secundus. The 40k background says that although they are designed to burn promethium most Imperial vehicles can burn other materials if necessary (but suffer a loss in performance). The players comtemplated getting wood from the forest until one bright spark suggested:

"Heretics burn don't they? How small will we need to chop him to get him in the firebox?"

The logical outcome was their new pet theory that heretics are made of Promethium. I think the cold had got to them by then.