I'm sure you can volunteer for anything. Just let them know about your deafness and of what you CAN and CANNOT do.
Here where I live, some members of the local deaf community are CERT members. CERT = Community Emergency Response Team, where a bunch of people volunteer their time to help out when there's a disaster going on (fires, tornadoes, earthquakes, etc.). To become a CERT, you attend the training clang sses to learn how to put out a fire with an extinguisher, first aid, what to do in this or that situation, if it's safe to go into a building or not, etc. As a matter of fact, the CERT Chiefs actually took the time to set up a class time ONLY for the deaf that were interested in becoming CERTs, and they hired 2 interpreters, and it was pretty fun. And they have gone far and beyond to accommodate the deaf CERTs by providing vibrating weather pagers (only the deaf CERTs have weather pagers I think...), and have invited someone from the fire station to a class to talk about the free alarm systems they have for the deaf, etc. They send out emails regularly to inform members of upcoming training sessions or classes, or events in which we can help out at like the Breast Cancer Walk for the Cure and the Air Shows (crowd patrol, helping people if a medical issue comes up, that sort of thing).
Definitely check out your local agencies and see what kind of volunteering opportunities they provide. They can't deny you from volunteering just because you are deaf; that'd be discrimination. We may not be able to use a phone or the walkie talkies (or anything that highly depends on hearing), but we are perfectly capable to do anything and everything else.