Don't forget that peanut butter, shrimp, eggs, milk and soy can be deadly without any contaminants at all, too. They claim food allergies kill up to 200 people in the U.S. every year. (Of course, lawn mowing kills even more people than food allergies.)
One of the benefits of becoming involved with E Cigs and snus for over three years is better understanding the principle of harm reduction. I've adopted that concept to lawn mowing. That's why mine looks more like a pasture than a lawn right now. However, I think I may risk hopping on the mower tomorrow.