It's official ... MISTER YUK [sic] is not just a logo -- he is used in text! From http://www.chp.edu/mryuk/05a_mryuk.php:
"Corporations have placed his face on the product labels of hazardous materials, and publishing companies have used the symbol in textbooks and standardized tests to represent poisons." -- Michael Everson *** Everson Typography *** http://www.evertype.com

