This allows a worker to KNOW through literature and other means, like video training, what dangers you may run into if you are about to handle any kind of material. Yes, even down to WD-40. It's called a SDS. (Safety Data Sheet) Or an MSDS. (Material Safety Data Sheet))
All dangerous ingredients listed.
ALL potential side effects listed.
Some chemicals can absorb right through your skin so you better know your PPE. Want to handle some butadiene? A worker can see what damage the product does so the damage can be prevented through safe handling.
And even with all of that information available at your fingertips you can't find out, right now, today, what it is you're about to inject into your body.
Sorry, boss, but if you aren't telling me what's in it I'm not working on it.
/crude analogy
A Perfect Explanation.
A Research Scientist *(a real one) who developed vaccines explained how all this protocol is against Clinical Research Ethics.
“The Government is not being transparent about the risks of the vaccine. People have the RIGHT to decide whether or not to accept an experimental vaccine. This is a fundamental RIGHT having to do with clinical research ethics. There are risks but no access to the data of the benefit ratio.”