16 U.S. Code § 18i - Federal employee status for volunteers
(a) Employment status of volunteers
Except as otherwise provided in this section, a volunteer shall not be deemed a Federal employee and shall not be subject to the provisions of law relating to Federal employment, including those relating to hours of work, rates of compensation, leave, unemployment compensation, and Federal employee benefits.
(b) Tort claims
For the purpose of the tort claim provisions of title 28, a volunteer under this subchapter shall be considered a Federal employee.
(c) Civil employees
For the purposes of subchapter I of chapter 81 of title 5, relating to compensation to Federal employees for work injuries, volunteers under this subchapter shall be deemed civil employees of the United States within the meaning of the term “employee” as defined in section 8101 of title 5, and the provisions of that subchapter shall apply.