I have permanent ringing in my ears too from both playing music, going to concerts, heck even blasting music at 100% as a kid with headphones probably contributed.
I would recommend anyone who goes to a Seahawks game or concert to wear ear plugs. It may be lame but 110+ decibels is no joke.
Some people can handle much louder noises without taking damage, some get permanent damage very easily.
According to this link @ 115 decibels 30 seconds is the maximum time you should be exposed. I'm guessing it's louder than 115 for a lot more than 30 seconds at a Hawks game. So unfortunately that is the kind of sound that could give a lot of people permanent hearing damage.
http://www.dangerousdecibels.org/educat ... uidelines/
I think hearing protection and loud sounds in general are one of the most serious health topics that nobody is really aware about. Our ears evolved to hear like thunder or battle screams as the loudest thing, not 100+ watt amps or thousands of people trying to set a Guinness world record in a stadium designed to amplify.
Hopefully your ears recover wear protection next time, it's lame but better than having ringing ears your whole life.
Oh but if you are going to wear earplugs you should get something that doesn't completely ruin the experience. Something like these are good for dampening the decibel level but you can still hear clearly without it being all muffled:
http://www.guitarcenter.com/Hearos-High ... 1134130.gc