I just got this in my email. I don't use retractable leashes but I just thought I'd give a heads up for those who do.

Retractable Leash Warning
Retractable leashes can be handy and more versatile than a regular leash. However, should something cause you to drop it, the leash may rewind, strike the dog, and cause him to flee in terror.

If you are using one with a wrist loop, be sure it is snugly in place and cannot slip off. If your leash doesn't have a wrist loop, either make one yourself or attach the handle to a belt loop with twine or whatever works for you.