Key Takeaways

  • Scene size-up follows a specific order: BSI/PPE first, then scene safety, MOI/NOI, number of patients, and additional resources
  • The NFPA 704 diamond uses four color-coded quadrants: blue (health), red (flammability), yellow (reactivity), and white (special hazards), each rated 0-4
  • The Emergency Response Guidebook (ERG) is used to identify hazardous materials by placard number and provides initial isolation and protective action distances
  • Hazmat zones are divided into hot (exclusion/contamination), warm (decontamination/reduction), and cold (support/safe) zones
  • EMTs operate at the awareness level for hazmat and should never enter the hot or warm zone without specialized training
  • START triage categorizes patients as immediate (red), delayed (yellow), minor (green), or deceased/expectant (black) based on RPM: respirations, perfusion, and mental status
  • JumpSTART triage is the pediatric modification of START triage used for children under age 8
  • PPE levels range from Level A (highest, fully encapsulated SCBA) to Level D (standard work uniform with no respiratory protection)
Last updated: February 2026

Scene Size-Up

The scene size-up is performed before making patient contact and follows a systematic approach every time:

Scene Size-Up Sequence

  1. BSI/PPE -- Body Substance Isolation is your FIRST priority. Put on appropriate PPE before approaching the scene.
  2. Scene Safety -- Is the scene safe for you, your partner, bystanders, and the patient? Look for hazards: traffic, fire, downed power lines, violence, hazmat.
  3. Mechanism of Injury (MOI) / Nature of Illness (NOI) -- Trauma: determine the MOI. Medical: determine the NOI based on the chief complaint.
  4. Number of Patients -- Are there more patients than your crew can handle?
  5. Additional Resources -- Do you need ALS, fire, law enforcement, utility companies, or hazmat teams?

NREMT Key Point: If the scene is NOT safe, do NOT enter. Stage at a safe distance and call for appropriate resources.


Hazardous Materials Awareness

EMTs are trained to the awareness level for hazmat incidents. This means you can:

  • Recognize a potential hazmat situation
  • Isolate the area and deny entry
  • Call for trained hazmat responders

You should NOT attempt rescue, decontamination, or containment at the awareness level.

NFPA 704 Diamond

The NFPA 704 placard (the "fire diamond") is found on fixed facilities and some vehicles:

QuadrantColorHazardRating Scale
LeftBlueHealth hazard0 (minimal) to 4 (deadly)
TopRedFlammability0 (will not burn) to 4 (extremely flammable)
RightYellowReactivity/Instability0 (stable) to 4 (may detonate)
BottomWhiteSpecial hazardsOX (oxidizer), W with line (reacts with water), SA (simple asphyxiant)

Emergency Response Guidebook (ERG)

The ERG is published by the US DOT and is used during the first 15-30 minutes of a hazmat incident:

  • Yellow section -- Look up the 4-digit UN number from the placard
  • Blue section -- Look up the material by name alphabetically
  • Orange section -- Provides safety and response information for each guide number
  • Green section -- Lists initial isolation and protective action distances for highlighted materials

Hazmat Zones

ZoneAlso CalledWho EntersPurpose
Hot ZoneExclusion zoneHazmat technicians onlyArea of contamination; requires Level A or B PPE
Warm ZoneContamination reduction zoneDecontamination teamsWhere decon corridors are set up
Cold ZoneSupport zoneEMS, command staffSafe area for staging, triage, and treatment

PPE Levels

LevelProtectionComponents
Level AHighestFully encapsulated suit, SCBA, chemical-resistant gloves and boots
Level BHighNon-encapsulated suit, SCBA, chemical-resistant gloves and boots
Level CModerateChemical-resistant suit, air-purifying respirator (APR)
Level DMinimalStandard work uniform, no respiratory protection

EMTs typically wear Level D (standard PPE: gloves, eye protection, mask) and operate in the cold zone only.


Mass Casualty Incident (MCI) Triage

START Triage (Simple Triage and Rapid Treatment)

START triage is used for adult patients during an MCI. Each patient assessment should take 30 seconds or less. The algorithm follows the RPM method:

  1. R -- Respirations: Can the patient breathe?
  2. P -- Perfusion: Is there a radial pulse or capillary refill <2 seconds?
  3. M -- Mental status: Can the patient follow simple commands?

Triage Categories

CategoryColorTagCriteria
ImmediateRedPriority 1Life-threatening but survivable with immediate intervention
DelayedYellowPriority 2Serious injuries but can wait 1-2 hours for treatment
MinorGreenPriority 3"Walking wounded" -- minor injuries, can self-evacuate
Deceased/ExpectantBlackPriority 0Dead or injuries incompatible with survival given resources

JumpSTART Triage (Pediatric)

JumpSTART is the pediatric modification for children under 8 years old:

  • If a child is not breathing, check for a pulse first
  • If pulse is present, give 5 rescue breaths and reassess
  • If the child starts breathing, tag immediate (red)
  • If no pulse, tag deceased/expectant (black)
  • Uses the AVPU scale instead of "follows commands" for mental status
  • "Inappropriate" posturing or unresponsive = immediate (red)
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START Triage Algorithm
Test Your Knowledge

During a scene size-up, what is the FIRST step an EMT should perform?

A
B
C
D
Test Your Knowledge

On the NFPA 704 diamond, which color indicates the FLAMMABILITY hazard?

A
B
C
D
Test Your KnowledgeMatching

Match each NFPA 704 diamond color to the hazard type it represents.

Match each item on the left with the correct item on the right

1
Blue
2
Red
3
Yellow
4
White
Test Your Knowledge

An EMT arrives at a hazmat scene. Where should EMS stage and begin treating decontaminated patients?

A
B
C
D
Test Your Knowledge

Using the START triage system, a patient who is not walking, has a respiratory rate of 24 breaths/min, has a radial pulse, and cannot follow simple commands should be tagged:

A
B
C
D
Test Your KnowledgeOrdering

Arrange the START triage decision steps in the correct order, from the first assessment to the last.

Arrange the items in the correct order

1
Determine if the patient can walk
2
Check respiratory rate
3
Assess perfusion (radial pulse / capillary refill)
4
Evaluate mental status (ability to follow commands)
Test Your Knowledge

In JumpSTART pediatric triage, what should the EMT do if a child under 8 is not breathing but has a palpable pulse?

A
B
C
D