Are you using the latest Form I-9?
When hiring temps, it's easy to use the forms you have laying around in the office - but you want to be careful that you're using the latest version! There are a million things to think about when running a staffing agency, and the tiny date on a government form probably isn't top of mind.
As you are probably aware, Form I-9 is used for verifying the identity and employment authorization of individuals hired for employment in the US. I would double check that you are using the latest Form I-9, which is a revision from July 2017. You can download the latest form from from the USCIS website. The proper form will have 07/17/17 at the bottom left corner.
These types of things are easy to overlook, but can be a huge headache if done wrong. Form I-9 is not updated all that often, so it's even easier to overlook than something that changes every year.
That's my advice to you for today, hope it helps!