Anyone working on a job as an independent contractor needs to furnish a certificate of their own workman's compensation insurance to the contractor of their services. (Or, if one person without workers an exemption certificate from the state here).

If not; the person contracting the sub-contractor needs to pay his insurance rate on his insurance policy here.

As I recall the laws on this in California are even stricter.

* Not legal advice. Workman's compensation laws will vary state by state.