On several synthetic lubricant products (that I know for sure use PAOs and not GroupIII/Dino oils), it says on the back:
CAUTION: CONTAINS SYNTHETIC LUBRICANTS. CAN CAUSE SKIN DISORDERS or something to that extent
On almost ALL dino oils, it says:
CAUTION: PROLONGED EXPOSURE TO USED MOTOR OIL blah blah
Now on Mercon-V, it says: "Contains Petroleum and synthetic lubricants. can cause skin disorders"
THis is true, Mercon-V is a synthetic blend.
Now why doesn't the new SuperSyn Mobil 1 have a caution regarding snythetic lubricants??? It just has the prolonged exposure to used motor oil cautionary statement.
Castrol Syntec has the Prolonged Exposure statement as well.
I know some people are EXTREMELY allergic to synthetic lubricants (real synthetics).