I second Mr. Tautech's safety recommendations
You're messing with substances that kill weeds,
and weeds are tough customers
that can and will grow even on concrete, not just in the cracks.
Imagine, or think about having sniffed that chemwarfare derived crap, the mist going into your lungs, eyes, skin, clothing, pet hair, private parts etc,
and wofting over into the neighbours vege patch etc
i.e. these 'defy nature' products have only been around a few decades,
and unless you are a chemical engineer come lab guru to perform your own DIY tests, and reach some sort of yes/no conclusion,
the average sprayer is clueless wth they are zapping their neglected lawn/jungle/swampland with.
And don't expect the jokers flogging this garden koolaid to give you the full story,
especially if any bad news is bad for business..