We told you a while back about a project to brainstorm methods for warning future civilizations about the dangers of nuclear waste dumps. It said, in part,
But the strangest suggestion by far came from two European linguists. They argued that governments around the world should breed cats that turn colors when exposed to radiation. These so-called “ray cats” could then be immortalized in song and legend, so that even after the scientific knowledge of radiation had been lost to the sands of time, folklore would tell of their supernatural power to change their fur in the presence of extreme danger.
Matthew Kielty investigated the “ray cat” solution, including tracking down Paolo Fabbri, the man who first conceived of the idea. Kielty posted about it, and people started trying to make it happen.
Emperor X produced an album of music about the ray cats, that includes the song “Don’t Change Color, Kitty!” Biologist Kevin Chen is looking into how we can make those cats a reality. He’s looking for collaborators on the project. -via Metafilter
We have an example of how effective such warnings are: Associated Press - Tsunami-hit towns forgot warnings from ancestors.
[EDIT: the article is no longer there, so here's a link to a related article in the NY Times.]
Centuries-old stone markers are scattered across Japan's coast, warning that earthquakes are followed by tsunami, and marking where buildings will be vulnerable. Some towns followed the warnings, and built homes only on high ground. Others ignored these warning stones. This is in a country where earthquakes and accompanying tsunami are pretty frequent!
More relevant is the frequency of incidents where radioactive metals find their way into scrap metal. Medical equipment containing radioactive Cobalt or Cesium sometimes ends up in junkyards after they are decommissioned. These devices are then disassembled, and the parts sold as scrap, including the radioactive 'source'. The scrap is sometimes melted down and mixed with steel to make reinforcing bars (rebar) for construction. Many incidents of this type are documented at Wikipedia. The contaminated rebar is sometimes intercepted before it is used in buildings, but sometimes it is not detected until long after installation. An apartment building in Taiwan, along with other buildings, is still being rented to tenants in spite of being built with radioactive rebar.
Radiomedical devices are clearly marked, and the containers for the radioactive 'source' material are built to be durable and are themselves well-marked with the familiar nuclear-trefoil. In spite of this, salvage of radioactive metals still occurs in many countries, resulting in the deaths of scrap-metal collectors, foundry workers and others. This is not an issue for untold generations in the future: we cannot even protect people today. Last year, radioactive rebar was found being used in India, and Mexican radioactive rebar was detected in a California scrap-metal facility.