More knowledge might help to prevent people from getting hurt.
If you must break up a dogfight.... then
The safest way to break up a dogfight requires 2 people. Each person grabs the back feet of one of the dogs. The dog's back feet are then picked up like a wheelbarrow. With the legs up, both dogs are then pulled apart.
Once the dog fight is broken up and the dogs pulled apart it is critical that the people do not release the dogs immediately or the dog fight may begin again. The two people need to start turning in a circle, or slowly swinging the dogs in a circle while they back away from the other dog. This stops the dog from curling and coming back and biting the person holding their legs.
By circling the dog has to sidestep with its front feet or it will fall on its chin. As long as you slowly continue to back and circle, the dog cannot do any damage to you. To insure that the fight will not begin all over again when you release the dogs, remove one of the dogs. After pulling the dogs away and circling, release the dogs slowly while calming them down by talking to the dog and letting the dog know it's you.
Dog fights are a very dangerous thing to try and break up alone. You should never rush in and try and grab the dogs to pull them apart. They are in high "fight drive" and are not thinking clearly when fighting.
This has been adapted from several dog training books and some websites that I've seen.