You are mistaken; legislation is not what achieved those. Massive, focused public scrutiny on pinpoint issues is what achieved those.
Passing legislation without the latter is meaningless, and if you have the latter, you don't necessarily need legislation; the free market will force a correction (although politicians will follow the will of the people anyway).
You cannot achieve that across the countless toxins and/or potential toxins that exist in our world; the public does not have enough attention to spare for that.
Or to put it more simply, regular people don't have the time or energy to spare on worrying about every little thing that could potentially, maybe be toxic, in some tiny way over decades.
> and if you have the latter, you don't necessarily need legislation; the free market will force a correction
The free market is very bad at solving problems with a lack of information. Efficient markets rely on buyers having a clear idea of what they're buying. You might hope that people are willing to pay for certification services or whatever, but this is not actually how naive consumers operate. There are already services like that and they operate on the fringes.
The notion that there is not enough public attention to ask for legislation about toxins as a general concept ("pinpoint" is demonstrably not needed), but there is enough attention for that same public to navigate an information marketplace about those toxins to make informed buying decisions, is laughable. Even more so when the former has actually happened multiple times and the latter remains a niche phenomenon.