They're Tobacco Chewin', Gut Chompin', Cannibal Kinfolk from Hell!

In the backwoods of America live a very special kind of people: Friendly, decent, hard-working dirt farmers. When they accidentally drink a barrel of nuclear waste, they turn into tobacco-chewing, flesh eating, cannibal kinfolk from hell. Meanwhile, seven sophisticated city slickers on vacation get lost in the woods and encounter a nightmare world of these illiterate and extremely insensitive undead. While the tourists hikers use all their wits and courage to stay alive, more and more 'down-home' types imbibe the nasty brew until Redneck Zombies are everywhere. What started as a scenic nature hike turns into a bloodbath of dismemberment and cannibalism.

IMDB

Personal note: This was the movie that introduced me to Troma and started the B movie watching parties I had in high school