[the8472]

Not inevitable at all. It's entirely feasible to specify categories of chemicals. E.g. see the german law on novel psychoactive substances[0] that lumps substituted molecules together with their primitive variants.

One could even go a step further and mandate outcomes instead of means, that substances must be proven to either have a low environmental half-life or to not bio-accumulate.

[0] https://www.gesetze-im-internet.de/npsg/anlage.html