Not sure to be honest with you, but they do have a volume control, so maybe just be careful with that?
I know those shures are really nice, but expensive.
Myself, I like the over the head earphones as they don't kill the inside of my ear canal. Just picked up some KOSS pro's and they sound fantastic! 20 Bucks at amazon! My dad just ordered a set and I bought him studio ones from AKG at over a 100 smacks and they sound better than those.
Yeah, they can seriously damage your internal ear if you listen to them loudly or for extended periods of time. But they offer good sound/performance if you're willing to pony up for a good pair of Etymonics, Shure, or Ultimate Ears.
i would think the noise cancelling headphones would be less damaging. you don't have to drown out any outside noises therefore the volume won't need to be up as high.