That was the Goiânia accident of 1987. To the best of my knowledge, it is the only such instance, which suggests that existing regulations around the safe decommissioning and disposal of such devices do a more reliable job of preventing accidental dispersal than booby-trapping equipment would - not to mention that this would make maintaining the equipment much more than usually fraught, besides.
And while these incidents aren't frequent, we are talking about very long time frames. It would be interesting if we could somehow look into the future and see how many incidents will occur.
Maintenance is a big concern. Although if we're willing to spend a lot of effort on how to label these things to appear obviously dangerous for long time frames then I think some time can also be spent on long term maintenance.
The whole idea behind the long-term warning project is that it should preserve its semiosis long after every other trace of its originating civilization has ceased to be detectable, so including maintenance in the remit would violate the fundamental premise.
(I don't think the premise is all that well founded, hence my original comment.)
Separately, the material in the Goiânia radiotherapy device was cesium-137, which has about a 30-year half-life, so any sample of given activity today would see that activity halved about 330 times over ten thousand years. I think it would take a much larger sample than typically found in medical equipment to remain hazardous at the end of that time! The long-term warning project has a somewhat narrower domain.
Comments
That was the Goiânia accident of 1987. To the best of my knowledge, it is the only such instance, which suggests that existing regulations around the safe decommissioning and disposal of such devices do a more reliable job of preventing accidental dispersal than booby-trapping equipment would - not to mention that this would make maintaining the equipment much more than usually fraught, besides.
Yep, this was the one I was thinking about.
And while these incidents aren't frequent, we are talking about very long time frames. It would be interesting if we could somehow look into the future and see how many incidents will occur.
Maintenance is a big concern. Although if we're willing to spend a lot of effort on how to label these things to appear obviously dangerous for long time frames then I think some time can also be spent on long term maintenance.
The whole idea behind the long-term warning project is that it should preserve its semiosis long after every other trace of its originating civilization has ceased to be detectable, so including maintenance in the remit would violate the fundamental premise.
(I don't think the premise is all that well founded, hence my original comment.)
Separately, the material in the Goiânia radiotherapy device was cesium-137, which has about a 30-year half-life, so any sample of given activity today would see that activity halved about 330 times over ten thousand years. I think it would take a much larger sample than typically found in medical equipment to remain hazardous at the end of that time! The long-term warning project has a somewhat narrower domain.