An unpowered alien pod drifts into our solar system. No particularly advanced technology is present on it. But the pod is full of ejected hazardous waste (say, between 10-1000 tons) from an alien civilization and dumped into interstellar space thousands or millions of years prior. Earth technology is several centuries advanced from the current time and there is no particular global crisis. When the nature of the hazardous waste is identified, conflict and war break out among those struggling to obtain the waste.
- It should be something an advanced civilization would have discarded like an industrial byproduct, and considered useless by the originating culture - hazardous enough they launched it into space rather than incinerating/recycling it.
- The waste must not be information or technology (like scriptures, nanites or broken warp coils), although it can be a product of technology that we can't produce (some sort of weird fullerene variant? Why would that be hazardous or useful?) I prefer not to have living waste (like psychic aliens making people value them)
- It must be so unambiguously valuable that humans are willing to break treaties and betray allies in order to possess it.
- I would prefer that it be a material, like unstable dark matter (just to make something up) or the whole thing consists of antimatter iron in a magnetic cradle.
- I would like it to be something that doesn't violate physics (no Pixie dust), ideally something that has been theorized to exist but not made/proven yet (like if there's a stable isotope of californium, if that's even possible, and why that would be useful).
- It should still be hazardous, so the risk in obtaining it is great, even without the conflict.
What is it that they've found aboard that pod? Explain why it is hazardous and why it is valuable, if that isn't readily clear.