Va. Code § 27-1
Whenever the necessity arises during any actual or potential emergency resulting from fire, personal injury, or other public disaster, the firefighters of any county, city, or town may, together with all necessary equipment, lawfully go or be sent beyond the territorial limits of such county, city, or town to any point within or without the Commonwealth, to assist in meeting such emergency.
In such event, the acts performed for such purpose by such firefighters and the expenditures made for such purpose by such county, city, or town shall be deemed conclusively to be for a public and governmental purpose and all of the immunities from liability enjoyed by a county, city, or town when acting through its firefighters for a public or governmental purpose within its territorial limits shall be enjoyed by it to the same extent when such county, city, or town is so acting, under this section or under other lawful authority, beyond its territorial limits.
The firefighters of any county, city, or town, when acting hereunder, or under other lawful authority, beyond the territorial limits of such county, city, or town, shall have all the immunities from liability and exemptions from laws, ordinances, and regulations, and shall have all of the pension, relief, disability, workers' compensation, and other benefits, enjoyed by them while performing their respective duties.
Va. Code § 27-1