N.Y.C. Admin. Code § 15-123: § 15-123 Limited mutual aid agreement with city of Mount Vernon.

a. Subject to the limitations contained in subdivision b of this section, the commissioner is hereby empowered to enter into a mutual aid agreement with the fire commissioner of the city of Mount Vernon. Such agreement shall authorize the dispatching of fire fighting equipment from the city of New York to the city of Mount Vernon when so requested by the commissioner of the city of Mount Vernon.

b. The scope of any agreement entered into pursuant to this section shall be limited in that fire fighting equipment dispatched from the city of New York shall only respond to fires or other emergencies occurring in that part of the city of Mount Vernon which contains the bulk oil storage installations located on the boundary line of the city of New York and within the confines of the city of Mount Vernon on either side of Eastchester creek.