A new ice age.
Saccharine causing cancer.
DDT wiping out birds (instead we have malaria wiping out populations).
Clackers
Jarts
Dangerous playground equipment
Corvairs
Pintos
Killer asteroids (maybe killer assteroids, yes)
EM emissions from your CRT
DC-10s
AIDs pandemic among heterosexuals
Disco
Eggs
Avocados
Bacon (mmmmmmm Bacon!)
Nuclear power
Concealed carry
Two of the most dangerous things on the planet !
Way more dangerous than that unmarked wormhole
LOL! Good list. Don’t forget Y2K
Radon Gas and Granite Countertops
What about Happy Fun Balls? Or deoderant destroying the ozone? Those were biggies for a while.