Tenn. Code § 58-8-113
In addition to any other authority provided by this chapter, any governmental entity may provide aid or assistance in any area of the state to any state or federal agency upon request by the state or federal agency, and the governmental entity and its employees will be subject to the same protections and immunities they have under this chapter in furnishing aid or assistance to other governmental entities. This section and any other portion of this chapter are in addition to and not in substitution for, and do not diminish, the authority provided in § 58-2-113 or any other law that authorizes a local governmental entity to respond to a request for aid or assistance from TEMA or any other state or federal agency. Nothing in this chapter shall be construed to require that employees of the responding party are to be considered employees of the state or any of its agencies for any purpose.
T.C.A. § 58-8-113