Re: Gravel driveway dust(cat poison)
Ethelene Glycol based antifreeze IS a liver toxin. It definitely kills, and it doesn't kill kindly.
The antidote is grain alcohol, vodka is an excellent antidote, most catshow people carry mini bottles of vodka at shows because certain a~~~es have taken to squirting EG antifreeze into cages at shows.
Poisoning varmints outside isn't a good policy cause predators will take advantage of the weakened varmint, and consume it. This leads to poisoning of everything up the food chain.
Trapping, is also a nasty way to go, unless you use a live trap, so you can releast the neighbor's pet, or even your own pet.
Calcium Cloride is a dangerous way to go too, especially if you have a well.
Used fryer grease is an excellent substitute for Calcium, and you can get it free.
If your concern is the carport, why not use dirtcrete?