Hazmat Incident Commander flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

UN/NA identification number

A four-digit number assigned to a hazardous material, displayed on orange placards and shipping papers, and used as the first lookup key in the ERG yellow pages to find the guide number.

NFPA 704 quadrant order

Health is blue on the left, flammability is red at the top, instability is yellow on the right, and special hazards are white at the bottom; the white quadrant shows W, OX, or SA.

Placard quantity threshold

Placards are required when 1,001 pounds (454 kg) or more aggregate gross weight of a single hazard class is loaded in one transport vehicle; bulk packages always require placards regardless of quantity.

ERG guide-page lookup order

Look up the four-digit ID number in the yellow pages, the material name in the blue pages, or the placard in the placard table, then read the resulting three-digit guide number in the orange pages.

CHEMTREC emergency number

1-800-424-9300 in the United States; it is the emergency response telephone number printed on shipping papers and provides 24-hour chemical emergency information to responders.

Initial isolation distances

The ERG recommends at least 150 feet (50 m) for a small spill, at least 300 feet (100 m) for a large spill, and 1,600 feet (500 m) in all directions when fire is involved.

Vapor density significance

A vapor density greater than 1 means the gas is heavier than air and will collect in low areas, basements, and sewers; less than 1 means it rises and disperses upward.

Specific gravity significance

A specific gravity less than 1 means the liquid floats on water and can spread burning product across a water surface; greater than 1 means it sinks and may enter water intakes.

Flash point definition

The lowest temperature at which a liquid releases enough vapor to form an ignitable mixture near its surface; it is the basis for classifying flammable versus combustible liquids.

LEL and UEL

The lower and upper explosive limits define the concentration range in air within which a vapor will ignite; outside that range the mixture is too lean or too rich to burn.

Risk assessment formula

Risk equals the probability of an adverse outcome multiplied by the severity of its consequence; the incident commander reduces risk by limiting exposure time, distance, and shielding.

Seven clues to hazmat presence

Occupancy and location, container shapes, markings and colors, placards and labels, shipping papers, sensory clues, and criminal or terrorist indicators together indicate that hazardous materials may be present.

Command transfer briefing

Command transfers face-to-face and includes incident conditions, actions taken, resources assigned, current organization, and safety concerns; the outgoing IC remains responsible until the briefing is complete.

Span of control

The number of subordinates reporting to one supervisor; ICS keeps this between three and seven, with five as the working target, adding divisions or groups when it is exceeded.

Hot, warm, cold zones

The hot zone contains the contamination and requires full PPE; the warm zone holds the decontamination corridor and access control; the cold zone holds command, staging, and medical support.

Unified command

An ICS application in which agencies with jurisdictional or functional authority jointly set a single set of incident objectives while each agency retains its own authority and accountability.

Two-in/two-out rule

At least two members must enter the hazardous area together while at least two equally equipped members remain outside, ready to rescue them, with entry times and air checks documented.

Defensive versus offensive operations

Defensive operations are conducted from outside the hot zone without entry; offensive operations require trained and equipped personnel entering with a defined rescue or leak-control objective.

Do not extinguish gas fire

A flammable gas fire at the source should not be extinguished unless the fuel supply can be shut off, because unburned gas will accumulate and may re-ignite explosively.

AR-AFFF foam use

Alcohol-resistant aqueous film-forming foam is required for polar solvents such as ethanol and methanol; standard AFFF breaks down and fails to seal the fuel surface on these materials.

BLEVE definition

A boiling liquid expanding vapor explosion occurs when a pressurized liquid container is heated above the boiling point of its contents and fails catastrophically, producing a fireball and projectiles.

Confinement versus containment

Confinement limits the spread of released material using dikes, dams, diversion, and absorbents; containment keeps material inside its original or overpack container using patches and plugs.

Level A protection

A fully encapsulating vapor-protective suit with SCBA worn inside, plus chemical-resistant gloves and boots; it provides the highest available skin, respiratory, and eye protection.

Level C restriction

An air-purifying respirator may be used only when the contaminant is known, its concentration is measured below the canister limit, and oxygen is at least 19.5 percent.

Permeation and breakthrough time

Permeation is molecular movement of a chemical through protective suit material; breakthrough time, measured by ASTM F739, determines how long a suit remains safe for a given chemical.

Decontamination corridor sequence

Tool drop, gross wash, primary wash, rinse, secondary wash and rinse, then suit removal, with monitoring at the exit point; all personnel and equipment leaving the hot zone pass through it.

Overpack drum capacity

A salvage drum accepts a leaking or damaged container that fits completely inside; a 55-gallon overpack holds containers up to about 85 gallons, and the original container must remain upright.

Chlorine kit A, B, C

Technician-level leak-control kits matched to chlorine container type and valve configuration; kit selection depends on whether the container is a cylinder, ton container, or tank car.

Dangerous when wet confinement

Materials in DOT Class 4.3 react with water to release flammable gas; confine by excluding water and covering with dry material, never with water spray, foam, or wet absorbents.

Pre-incident plan contents

A site-specific plan documents chemical inventory and SDSs, container types, water supply, access routes, staging and command locations, evacuation zones, and target hazards for the facility.

HAZWOPER training hours

OSHA 29 CFR 1910.120 requires 40 hours of training for general site workers, 24 hours for occasional site visitors, and 8 hours of annual refresher training for both.

National Response Center reporting

CERCLA requires reporting releases of reportable quantities to the National Response Center at 1-800-424-8802, the federal notification point for hazardous materials releases.