The Emergency Service Unit (ESU) is part of the Special Operations Bureau of the New York City Police Department. The unit provides specialized support and advanced equipment to other NYPD units. Members of ESU are cross-trained in multiple disciplines for police, medical, and rescue work.

ESU is always on patrol (all three tours, 365 days a year) with 10 Heavy Rescue trucks, each ordinarily manned by a police officer and a sergeant, and often more than twice as many smaller Radio Emergency Patrol vehicles containing two ESU police officers. There are also two or more citywide patrol sergeants or lieutenants in unmarked vehicles on duty at all times to supervise ESU operations where needed. These are called "U-Cars" on the NYPD radio, for example, "U-5".

On July 7, 1925, former Police Commissioner Richard E. Enright established the Emergency Automobile Squad, which was the forerunner to today's ESU.^[5] The unit was created in order to address problems with growing urbanization in NYC that were beyond the capabilities of regular patrolmen. The first two units, Squad 1 (Manhattan / Bronx) and Squad 2 (Brooklyn / Queens) were staffed by six sergeants and forty-four officers. In September 1926, Police Commissioner George McLaughlin formed Squad 3, which was dedicated to the Bronx. It was also at that time that the name was changed from Emergency Automobile Squad to the Emergency Service Squad.^[6] In May 1928, Police Commissioner Joseph A. Warren doubled the number of existing units.^[7] By 1929, the Emergency Service Squad consisted of eleven trucks and was staffed by over 250 sergeants and patrolmen, and an additional nine trucks and over 200 more personnel were scheduled to be added in January 1930.^[8]

From its inception, ESS had been under the control of precinct commanders, who lacked the training and expertise necessary for the efficient use of the unit's manpower and equipment. On April 10, 1930, Police Commissioner Grover A. Whalen issued General Order #20 ^[9] which created the Emergency Service Division and also placed it under the command of Inspector Daniel E. Kerr.

The Emergency Service Unit currently utilizes numerous vehicles including:

• 11 Heavy Rescue trucks which are referred to as "Trucks". Trucks were built by E-One
• 40 Radio Emergency Patrol (REP) trucks, which are referred to as "Cars", are ESU's work horse and used for regular patrol. Each REP is equipped with SCUBA gear, emergency medical equipment, rope rescue equipment, forcible entry equipment and rescue equipment including hydraulic rams and the Hurst Tool (Jaws of Life). REP trucks are built by Odyssey Specialty Vehicles.^[12][13]
• ESU's Emergency Medical Squad mans two ambulances.^[14]
• Four Lenco BearCat and two Lenco Peacekeeper armored vehicles 1 International POT (Photo Observation Truck), 1 Lenco BEAR (Ballistic Engineered Armored Rescue Vehicle).
• 14 portable light tower generator units stationed throughout the city. In addition to the towers, ESU can also deploy 60 kW, 90 kW, 100 kW and 200 kW generators upon request for additional power when required.
• Four Mobile Light Generators which are specialized light-power units with tower generators mounted in the bed of pickup trucks.^[15]
• 100 kW mobile generator trucks designated as Mobile Auxiliary Light Truck (MALT)s. It has the capability of supplying enough power to light up Grand Central Terminal.^[16]
• Construction Accident Response Vehicles (CARV) which responds to construction accidents and is used to stabilize structures and rescue entrapped workers/personnel.^[17]
• Emergency Support Vehicle (ESV) which is complete with a motorized Zodiac inflatable boat and deployable rescue airbag.^[18][19]
• ESU also has 12 jet skis, plus numerous Zodiac inflatable boats assigned to units throughout the NYPD.

• NYPD ESU Heavy Rescue Truck 9
• 2 NYPD ESU REP trucks from ESS 10

The personnel selected for ESU become highly trained members of the NYPD who perform rescue, SWAT and other high risk tactical, counter-narcotic and counter-terror operations.

There are minimum time-in-grade requirements before an NYPD officer can apply to transfer to ESU. Police Officers must have a minimum of 5 years in the department with a minimum annual rating of 3.5. Supervisors in the rank of sergeants and lieutenants must have 2 years in rank before being assigned to ESU. In addition, all ESU candidates must be approved by a group of current ESU members to ensure that they will integrate into the unit successfully.

Applicants have to complete the Specialized Training School over eight months receiving training in multiple disciplines including tactical, search and rescue, hazardous materials containment and become certified in SCUBA diving and as an Emergency Medical Technician.^[20][21] Tactical training includes room clearing, team movements, close quarter battle, a week of active shooter training and three weeks of specialized and heavy weapons training.^[22] ESU officers are equipped with the Colt M4 Commando rifle.^[23][24]

ESU lost more members (14 out of 23 NYPD officers) than any other NYPD unit during the World Trade Center attacks on September 11, 2001.^[25]

• SWAT
• New York City Police Department