>>With the popular use of noise-canceling earphones, you can easily damage your hearing.

Sure about this?

Damage comes from long term exposure to high volume sound. Higher volume sound can be pictured as larger waves. Noise cancellation does exactly that; it produces an opposite wave of nearly the same height, resulting in much reduced peaks - so there's no need to raise the volume of whatever you're listening to well above ambient noise.

That said, sure, it's possible to push the volume high enough to eventually cause damage - but noise cancellation makes that less likely not more.

Also, the thing to beware of is impact noise. The classic example is gunfire (speaking as someone who used to compete and was paranoid about my hearing). But there's also any kind of banging (e.g. hammer on nail or anvil).