The man who started it all.
In the spring of 1940, an unidentified criminal fell into a tub of goo. From this tub of goo emerged The Joker, and the world has never been the same. Clayface, Mr. Freeze, Two-Face, Solomon Grundy, Parasite, all fell victim, in one way or another, to tubs of goo. Christ, the Creeper fell into the same tub of goo as the Joker! You would have thought that having one person turn into a raving psycho would be enough for that company to stop manufacturing that particular brand of goo, but that's corporate America for you.
(In the film Batman and Robin, even Poison Ivy falls into a tub of goo, although her comic-book counterpart did not seem to need to take it that far.)
Where would we be without tubs of goo? How many of our psychotics, mutants and monsters owe their existence to tubs of goo?
And not just villains, good guys too. Flash fell into a tub of goo too, and was struck by lightning to seal the deal. Metamorpho, Plastic Man, Swamp Thing -- all goo-produced phenomena.
Over in the Marvel universe, in addition to having their own swamp thing called Man-Thing (who fell into the same tub of goo as Solomon Grundy but with vastly different effect) they actually have a tub of goo from outer space, one that will actively seek out people and jump on them, turning super-heroes bad and bad guys evil.
(It should be noted that the Marvel Universe seems to be plagued with radiation instead of tubs of goo, perhaps as a symptom of coming of age after the H-bomb testing began.)
Where is the anti tub-of-goo legislation? Or just lids, what about lids? Just put some goddamn lids on the tubs of goo, would that be so hard? Bruce Wayne needn't have changed his life and become a fearsome creature of the night, he could have just sprung for some lids and his city would have been perfectly safe.