So, I would say first and foremost, do you have good contracts/agreements in place? Also, you need to be sure that the people you are calling "contractors" are really contractors.
That is, you must be very careful to abide by the IRS rules regarding "contractors" (i.e., 1099 workers). Contractors should all have specific self-determining kinds of work to do, normally in a finite time period, with defined deliverables, using their own place of work, and so forth.
If you look at section two of the IRS publication 15-A, you will see exactly what the IRS considers when determining whether a worker is an employee or an independent contractor (i.e., 1099 worker).
In addition, the IRS will help an organization free of charge to determine the appropriate classification for a worker or group of workers in the organization in regards to federal law. To obtain that service, you simply complete and submit IRS Form SS-8. However, your state may have different requirements.
Some P&C brokers will let you insure your contractors on your workers compensation policy. You will need to ask yours to see how she handles such requests.