The problem is that they have to have some number, otherwise they'd essentially be banning balloons.
So? Ban them. If they're harmful, they're harmful. Legislation like this annoys me because it's another case of "See... we're doing something about this horrible problem
(Not really) " without actually doing anything. It's precisely the same as so many of these other so-called environmental protection laws wherein they say, "This or that chemical is a hazard, but it's okay if you only let a little bit spill into the water supply".
I don't necessarily disagree with you.
It takes a long time to ban something, unfortunately. If you ban something, you're essentially shutting down a business or parts of a business. People cry that government is taking over and that people will lose jobs. One of the biggest ways to get your voice heard is to claim people will be jobless. We're a very self-centered species. We only seem to care what's good for us in the here and now. People cry that coal plants are getting shut down and people will lose their jobs. It's funny how they don't seem to comment or care about how those coal plants are causing degradation to the environment or causing negative health affects to people that live nearby or downstream/downwind.
Look how long it's taking to try to ban plastic bags... areas have resorted to charging per plastic bag, and people still use them.
Regarding chemicals, sometimes it really is chemical specific regarding additives to water/wastewater used by industries. That said, I don't think "spills" into a water supply should ever be taken lightly. Otherwise, discharge of chemicals (at "safe" levels) have been reviewed and approved by the state government here in the US.
If anyone has qualms with laws, regulations, or company permits, they should comment to their regulators and comment on draft permits that are publicly noticed. Unfortunately, many people that do all the complaining never actually force regulators to legally respond to their comments because they don't do it as part of the public participation process. If you write a letter to a regulator or send a tweet, they don't really have to respond to you, or if they do, it'll be some "oh, we care about our electorate" statement. But, if you write a letter during the public participation of a draft permit that's going to be approved and you have some really good scientific points that will counter what the state is going to approve, they have to respond to your comment in some meaningful way, lest they risk litigation.