I have had a couple of individuals work for me for a couple of months each during the current tax year. One left to parts unknown without notice, the other was fired. I have last known addresses on both but no SS #'s. I want to file 1099s but need to know what to expect from the IRS with 1099's that lack the SS numbers. This was my first year with employees in this business so trust me the paperwork will be filled out at hiring time in the future.

You must issue Form 1099-misc if payment to contractor is $600 or more in a year.
For each 1099-misc without SSN, you will pay $50 penalty.