N.J. Stat. § 40A:14-156
In the event of an emergency the chief or other head of any municipal police department and force or any park police department or system, municipal fire department and force, volunteer fire company, or first aid or ambulance squad, corps or company, or the mayor or chief executive officer of the municipality may request, from the chief or other head of the police department and force of any other municipality, assistance outside the territorial jurisdiction of the department to which such request is directed for police aid, in order to protect life and property or to assist in suppressing a riot or disorder and while so acting, the members of the police department and force supplying such aid shall have the same powers and authority as have the members of the police department and force of the municipality in which such aid is being rendered. Said members shall also have, while so acting, such rights and immunities as they may otherwise enjoy in the performance of their normal duties in the municipality, or other territorial jurisdiction, rendering such assistance.
The chief or head of the police department and force to whom such a request for assistance is made shall, in the case of a contiguous municipality, provide such personnel and equipment as requested to the extent possible without endangering person or property within the municipality rendering such assistance.
Any municipality receiving assistance hereunder shall pay to the police department and force providing the assistance a sum computed at the rate of $3.00 for each member and $5.00 for each vehicle for each hour supplied unless terms and conditions for payment are otherwise provided for in an agreement between the several municipalities.
If any member of such other police department and force in rendering such assistance shall suffer a casualty or death, he or his designee or legal representative shall be entitled to all salary, pension rights, workmen's compensation and other benefits to which such member or officer would be entitled if such casualty or death occurred in the performance of his normal duties in the municipality, or other territorial jurisdiction rendering such assistance.
N.J.S. § 40A:14-156