I donno. Being using all these chemicals for god know how many years already, but only during weekends and under my open porch la. I'm still alive and kicking and my skin hasn't turned to green yet, nor do I have any of my nails falling away. I think all these 'safe for use' is being blown out of proportion. I mean, these stuffs had been on the shelf for years and are still selling well. There must be a reason for it.
I also noticed the misconceptions on the products INTENDED usage. There are those products for the normal consumer (average Joe), bodyshops (Professionals) and Pro-sumer (people like us). I'm in the opinion that Optimum products are marketed for Pro-sumer, i.e. people who know about detailing products, what they do and take detailing seriously (might or might not do commercial details), but don't have a fix or permanent facilities to get a controlled environment. Therefore they needed something that's 'reasonably' safe to use, to both their person or the vehicle. To get this, there need to be a compromise on the 'potentcy' or 'effectiveness'. Products like Meg's Super Degreaser or Osren DegreaserFX are, however, marketed SPECIFICALLY for bodyshops, i.e. to those who have a permanet facilities where safety can be controlled through using safety equipments and attires (supposedly, but unfortunately most Malaysian places don't adhere to them). These bodyshops concerns only with time as, to them, time is money. So they need something that could work effectively, 'relatively' safe and, most importantly, FAST.
Yes, OPC is a strong and effective cleaner and degreaser, but it's not as strong nor can work as fast as, for example, DegreaserFX or Meg's Super Degreaser. But, as above, OPC is for the pro-sumer and the Meg's are for bodyshops. If you want to use those products that are meant for bodyshops, of course you'd need to take the necessary precautions. If you don't think you can do that, then OPC would be a better choice, but you'd still need to take some precautions as required.
End of the day, whether it's caustic chemicals or 'safe' chemicals, it all boils down to the person who uses them. If it's harmful to you then take the necessary precautions or change to something else. Just USE THEM WISELY as oppose to BLINDLY.
Regards.