There's a difference between a proprietary formula and not disclosing the ingredients.

Take Coca Cola for example. The ingredients are listed on the bottle/can. The FORMULA is sealed in vault with security that probably makes Fort Knox look like a school locker.

Yes, the MSDS does address health issues, but those change. What happens when a product that was considered safe no longer is? Without revealing the ingredients (not the formula, but the ingredients), you leave the clients reason for concern.

You need look no further than the recent discussion about BabbitRite and how the "secret sauce" in that product was none other than good old asbestos. Without the proper info, how does anyone know what risks may be found here.

I can totally understand not revealing the formula. That's a trade secret, and should be protected. But not revealing the ingredients makes you wonder if there is a reason for that. Typically the reason falls in one of two categories. 1) We don't want people to know it contains something hazardous. 2) We don't want people to know it's something so common and simple they could make it themselves for next to nothing.