Case-by-case analysis is really expensive for a government agency to do. And you know full well that developers will cut corners at any chance they can if the rules are loosened up.
If we banned all uses of harmful substances, many things (e.g. spaceflight) wouldn't be possible (or at least much more expensive) (e.g. most hypergolic propellant used for fine maneuvring e.g. during docking are extremely poisonous - alternatives are being tested but aren't there yet).
Case-by-case could be an industry wide standard with Operations & Maintenance requirements, which is what we currently have in real estate surrounding existing asbestos and lead applications. A similar protocol surrounding implementation of new "safe" installations of asbestos-containing-materials could be developed.