Below you can find the Though chemists call it a noble gas the epa calls it the #1 united states radiation health risk Jeopardy Words Answer. The answer to Though chemists call it a noble gas the epa calls it the #1 united states radiation health risk has 5 letters. This clue belongs to the The elements category and is part of Jeopardy Word Level 1728. If you scroll near the bottom you will find other clues and answers part of level 1728