Understanding NERIS Incident Type Codes

How NERIS Codes Work

NERIS incident type codes follow a 3-tier hierarchical structure: Group → Sub-group → Incident Type. Unlike NFIRS, which used a fixed set of numeric codes like "111" for "Structure Fire," NERIS codes are human-readable strings that describe exactly what happened.

The full code for a structure fire with structural involvement looks like this:

This three-part structure means you always know exactly what you're looking at — no code lookup table required. It also means the system can accommodate new incident types (like EV battery fires or drone incidents) by adding new codes within existing groups, without breaking the entire taxonomy.

The Core Coding Principle

Before walking through each group, there's one rule that shapes every coding decision in NERIS:

Code the incident for what actually happened — not the worst case you feared when you dispatched.

Examples of what this means in practice:

• A smoke investigation that turned out to be cooking smoke → HAZSIT / INVESTIGATION / SMOKE_INVESTIGATION, not FIRE
• A lift assist where the patient didn't require transport → PUBLIC_SERVICE / LIFT_ASSIST, not MEDICAL
• A motor vehicle accident with no injuries → HAZSIT / HAZARD_NONCHEM / MOTOR_VEHICLE_COLLISION, not RESCUE
• A motor vehicle accident with entrapment → RESCUE / TRANSPORTATION / MOTOR_VEHICLE_EXTRICATION_ENTRAPPED

The same underlying event codes differently depending on what you actually found. This requires crews to code after the incident is resolved, not at dispatch.

The Six Major Code Groups

FIRE — Fire Incidents

The FIRE group covers all incidents where combustion was the primary hazard. Sub-groups include structure fires, vehicle fires, wildland fires, and other fires (dumpster, outside, etc.).

• FIRE / STRUCTURE_FIRE / STRUCTURAL_INVOLVEMENT_FIRE — fire has spread to structural components
• FIRE / STRUCTURE_FIRE / CONFINED_FIRE — fire contained to object of origin, no structural involvement
• FIRE / VEHICLE_FIRE / CAR_FIRE — passenger vehicle fire
• FIRE / VEHICLE_FIRE / ELECTRIC_VEHICLE_FIRE — EV battery or drivetrain fire
• FIRE / WILDLAND_FIRE / GRASS_FIRE — grass or brush fire
• FIRE / OTHER_FIRE / DUMPSTER_FIRE — trash, dumpster, or outside refuse fire

MEDICAL — Medical Emergencies

The MEDICAL group covers incidents where the primary problem is a medical condition. It's divided between INJURY (trauma) and ILLNESS (medical condition) sub-groups.

• MEDICAL / ILLNESS / CARDIAC_ARREST — cardiac arrest requiring resuscitation
• MEDICAL / ILLNESS / STROKE_CVA — stroke or cerebrovascular accident
• MEDICAL / ILLNESS / RESPIRATORY — respiratory distress
• MEDICAL / INJURY / TRAUMATIC_INJURY — trauma from a fall, assault, etc.
• MEDICAL / INJURY / MOTOR_VEHICLE_COLLISION — MVC where someone was injured and transported

HAZSIT — Hazardous Situations

Hazardous situations cover incidents involving chemical hazards, non-chemical hazards, and investigations where a hazard was suspected but not confirmed. This is where most coding confusion occurs.

• HAZSIT / HAZARD_MATERIAL / GAS_LEAK — confirmed natural gas or LP gas leak
• HAZSIT / HAZARD_MATERIAL / FUEL_SPILL — petroleum product spill
• HAZSIT / HAZARD_NONCHEM / MOTOR_VEHICLE_COLLISION — MVC with no injuries
• HAZSIT / INVESTIGATION / SMOKE_INVESTIGATION — smoke reported, no fire found
• HAZSIT / INVESTIGATION / GAS_ODOR — gas odor reported, leak not confirmed

RESCUE — Rescue Operations

Rescue covers incidents where the primary action was extricating or recovering a person from a life-threatening situation — not a medical emergency per se, but a physical rescue.

• RESCUE / TRANSPORTATION / MOTOR_VEHICLE_EXTRICATION_ENTRAPPED — occupant trapped and requiring extrication
• RESCUE / WATER_RESCUE / SWIFT_WATER — swift water rescue
• RESCUE / CONFINED_SPACE / INDUSTRIAL — confined space rescue in industrial setting
• RESCUE / HIGH_ANGLE / CLIFF_RESCUE — rope/high angle rescue

PUBLIC_SERVICE — Non-Emergency Responses

Public service covers calls where the department responded but the incident was not an emergency in the traditional sense — alarms, lift assists, welfare checks, and service calls.

• PUBLIC_SERVICE / LIFT_ASSIST — patient on floor, department assists but no transport
• PUBLIC_SERVICE / ALARMS / SMOKE_ALARM_ACTIVATION — smoke alarm activation, no fire found
• PUBLIC_SERVICE / ALARMS / CO_ALARM — carbon monoxide alarm activation
• PUBLIC_SERVICE / LOST_PERSON — missing person search
• PUBLIC_SERVICE / WEATHER_RESPONSE — storm damage, flooding assistance
• PUBLIC_SERVICE / PERSON_IN_DISTRESS — welfare check, person in need of assistance

NO_EMERGENCY — False Alarms and Good Intent

Every cancelled call, false alarm, and good-intent call must still be reported in NERIS. These records are used to track false alarm trends and assess departmental workload.

• NO_EMERGENCY / FALSE_ALARM / MALICIOUS — intentional false report
• NO_EMERGENCY / FALSE_ALARM / ACCIDENTAL — accidental activation, unintentional
• NO_EMERGENCY / GOOD_INTENT / CANCELLED — call cancelled en route
• NO_EMERGENCY / GOOD_INTENT / WRONG_LOCATION — responded to incorrect address

Common Coding Mistakes

These are the coding errors that show up most frequently in NERIS data quality audits:

• Using MEDICAL for lift assists — lift assists with no transport should be PUBLIC_SERVICE / LIFT_ASSIST. Only code MEDICAL if there was a medical condition being treated.
• Using FIRE for smoke investigations — if you responded to a smoke report and found no fire, it's HAZSIT / INVESTIGATION / SMOKE_INVESTIGATION.
• Using HAZSIT for MVC with entrapment — if someone was trapped and required extrication, that's RESCUE, not HAZSIT.
• Leaving cancelled calls out — all calls, including cancellations, must be reported. Use NO_EMERGENCY / GOOD_INTENT / CANCELLED.
• Coding at dispatch, not resolution — the incident type should reflect what you found, not what dispatch thought it might be.