You write as if it would not be possible to work with these chemicals safely at a reasonable cost, and that's just not true. Other jurisdictions manage this.
Corporations naturally seek to improve margins, all the time, constantly. They will push and push against rules and regulations. It's the proper role of government to balance the costs to the corporation against the interests of the public. And it can be done well. But in the US, it's becoming more and more rare.
Which "Other jurisdictions manage this"?
I have lived in places with more rules, but that meant we just didn't do it. We eventually gave up.
I have read the rules are tighter in most EU nations.
There is jurisdiction shopping of course. If china or wherever wants to have really lax rules, and that means production moves there, I’m not sure what the answer is.
But, for this product (making plexiglass like things), I expect all the consumer production has gone overseas anyway. This is defense / aerospace, so it probably can’t move.
The answer is actually really easy, and it's been implemented successfully before: selective import taxes.
You set import taxes so that they offset price advantages. If a country has shitty environmental laws, crappy labor protections, etc. then you prices that into their import taxes. That way they don't gain any advantages in a race to the bottom based on things that you care about in your own country.
If a country adopts better environment laws, labor projections, etc. then you lower the import tariffs you charge on that country's relevant goods
Or we could just let it go offshore? Do we have to do everything here?
They are not saying that we have to do everything here, they are saying: If you want to move your mfg. to a country that has less environmental regulation enforcement, labor law enforcement and other things that we care about here, then the goods you are shipping back should be tariffed accordingly.
If we as a people pass environmental laws & labor laws because we feel that these things are important then why are we accepting products that are made in violation of our standards.
But... but taxes and tariffs bad!!!
Snark aside, the widespread lack of understanding of basic economic concepts is actually a real problem. On one side, you got an utter buffoon like Trump acting like taxes and tariffs are his personal revenge sledgehammer to wield however he wants, and on the other side you got (an awful lot of) short-term rewarders who will accept just about any predictable long-term consequence for short-term "lower prices for consumers".