http://hoaxbusters.ciac.org/HBUrbanMyths.shtml#swiffer
Swiffer Wetjet Kills Dogs Warning
May 2004
This one claims that the cleaning solution in Swiffer Wetjets contains antifreeze and kills your pets if they walk on a cleaned floor. If you check the ingredients in the material safety datasheet at the Proctor and Gamble website, you see that it does contain 1% to 4% percent Propylene Glycol n-Propyl Ether. Now Propylene Glycol is one chemical used to make antifreeze, the other is Ethylene Glycol, however the concentrations in antifreeze found in your car is around 50% not 4%. According to the ASPCA, while Ethylene Glycol is known to cause liver damage in animals, Propylene Glycol in the concentrations used in the Swiffer Wetjet cleaning fluid is not a hazard for animals.