My personal rule is that the sound level should be comfortable without ANC. So, if the sound is physically dampened sufficiently by the earbuds or headphones even when ANC is disabled, I'm happy.

ANC is more for comfort than safety from what I understand.

I can't say that the feedback causes damaging levels of noise, and its possible that my hearing is still protected, but the feedback that is produced is so uncomfortable that I involuntarily pulled them out of my ears.. which is not a great reaction with power tools in hand.

Apple does market 'Hearing Protection' as a feature of the AirPods Pro. https://support.apple.com/en-us/120850

Looking at the ANSI Datasheet, it seems like it's not really suited to the sounds coming from all power tools since they can reach or exceed 110 dBA:

> The Hearing Protection feature is not suitable for protection against extremely loud impulse sounds, such as gunfire, fireworks, or jackhammers, or against sustained sounds louder than 110 dBA.

I suppose if you know your tools operate at 110 dBA or lower levels, you're good to go. The feedback is bizarre though... Hopefully Apple resolves that with a firmware update!

Edit: It looks like it can safely attenuate sound at 110 dBA for 16 to 63 hours. That's impressive!

Active noise cancellation does not provide noise reduction and active noise cancellation headphones generally don't have official NRRs.

Closed headphones or foam ear plugs would be better than earbuds with ANC. People have tried to create informal amateur NRR ratings for many consumer headphones, but since it's your only pair of ears in my opinion it makes sense to go for officially rated hearing protection.

If you have sensitive ears you can tell ANC works by playing audio and that it's far from perfect. In very loud environments there's also the risk that a damaged earbud will squeal or feedback, disabling noise protection and exposing your ear to the full brunt of the loud noise.

Apple provides SNR values for ANC on the APP3 https://regulatoryinfo.apple.com/hearingprotection/details/6...

> foam ear plugs

I tried them for several weeks, everyday and ended up with annoying ear infections. Also they are quite uncomfortable to wear when sleeping.

I'm not, and should probably get a more specific product as recommended by abakker.

I can say I've used ANC in-ear and over-ear of various implementations for years without experiencing discomfort typically associated with ANC 'pressure'.