Together with radium and transuranium elements, actinium is one of the most dangerous radioactive poisons with high specific α-activity.

In a quick search of medical journals, he could find only one article describing the deliberate use of a radioactive poison to kill.

The world was warned of the dangers of nuclear accidents 25 years ago, when Chernobyl exploded and lofted radioactive poisons into the atmosphere.

Leona speculated that a water leak was the problem, rather than a radioactive poison.

The timings now pointed to a radioactive poison.

The air was sweet and clean, now, but manlike creatures had died by hundreds when the radioactive poison reached them even here.

Explosives would be out of the question, and a radioactive poison of some kind appears to offer the greatest hope of success.

The agreements set requirements and timetables for disposing of radioactive and chemical poisons that accumulated during the cold war at the nation's nuclear-weapons plants.

The occupying terrorists warned that any attempt by authorities to approach the building would be met by the release of radioactive poisons into the city.

The most promising haven he found was a small group of islands off the coast of South America where the radioactive poison would never reach.