29 CFR 94.640: Employee.

(a) Employee means the employee of a recipient directly engaged in the performance of work under the award, including—

(1) All direct charge employees;

(2) All indirect charge employees, unless their impact or involvement in the performance of work under the award is insignificant to the performance of the award; and

(3) Temporary personnel and consultants who are directly engaged in the performance of work under the award and who are on the recipient's payroll.

(b) This definition does not include workers not on the payroll of the recipient (e.g., volunteers, even if used to meet a matching requirement; consultants or independent contractors not on the payroll; or employees of subrecipients or subcontractors in covered workplaces).