If I recall correctly the maximum Noise Reduction Rating (NRR) for earplugs and earmuffs is around 30db. You can combine the two for a slight increase in hearing protection but you still hit a limit because of bone vibration.
Is there PPE out there to go even further beyond this? Where would it be commonly used?
This may only be within the range of human hearing, and you can and do still suffer damage from excessive amplitude by frequencies above and below what is human detectable. ANC is not a protective technology for this reason, it is a quality of life technology.