Under guidelines prescribed by the Secretary and concurred with by the Attorney General, employees of the Department of Energy and employees of contractors and subcontractors (at any tier) of the Department of Energy, while discharging their official duties of protecting the Strategic Petroleum Reserve (established under part B of title I of the Energy Policy and Conservation Act [42 U.S.C. 6231 et seq.]) or its storage or related facilities or of protecting persons upon the Strategic Petroleum Reserve or its storage or related facilities, may—

(1) carry firearms, if designated by the Secretary and qualified for the use of firearms under the guidelines; and

(2) arrest without warrant any person for an offense against the United States—

(A) in the case of a felony, if the employee has reasonable grounds to believe that the person—

(i) has committed or is committing a felony; and

(ii) is in or is fleeing from the immediate area of the felony; and

(B) in the case of a felony or misdemeanor, if the violation is committed in the presence of the employee.