Dear Christopher Cat: I live in the country and have indoor-outdoor cats. I know automotive antifreeze is deadly to animals, but people say Sierra is a safe alternative. Should I replace my car’s coolant with Sierra?
Christopher Responds: Standard antifreeze contains ethylene glycol (EG), which is very toxic to cats, dogs, wildlife and children. It’s enticing because it tastes sweet, and when outdoor water bowls freeze, puddles of EG antifreeze may be the only liquid available to a thirsty animal. Even a few drops can be fatal to a cat.
A safer antifreeze option is propylene glycol (PG). No coolant is completely safe, but PG coolants like Sierra and Prestone LowTox are considerably safer than EG. Ask your mechanic about switching to a PG coolant such as Sierra.
Until then, if you ever see a puddle of the telltale yellow-green EG antifreeze, sop it up with paper towels, and dispose of it all in a trash bag. Don’t hose down the area, as that only spreads the poison, which remains toxic even when diluted.