Hazmat Incident Commander cheat sheet

UN/NA four-digit identification numbers appear on orange placards, in the ERG yellow-bordered pages, and on shipping papers; the same number identifies the material in all three places.

ERG 2024 guide-page lookup order: (1) four-digit ID number in yellow pages, (2) material name in blue pages, (3) placard/rail car in the table of placards; the three-digit guide number is then read in the orange pages.

NFPA 704 quadrant order is health (blue, left), flammability (red, top), instability (yellow, right), special hazards (white, bottom); the white quadrant uses W (water-reactive), OX (oxidizer), SA (simple asphyxiant).

DOT hazard classes: 1 explosives, 2 gases (2.1 flammable, 2.2 nonflammable, 2.3 toxic), 3 flammable/combustible liquids, 4 (4.1 flammable solid, 4.2 spontaneously combustible, 4.3 dangerous when wet), 5 (5.1 oxidizer, 5.2 organic peroxide), 6 (6.1 toxic, 6.2 infectious), 7 radioactive, 8 corrosive, 9 miscellaneous.

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

Clues to identification: container shape and size, placards and labels, shipping papers, pipeline markers, facility pre-plans, occupancy, and sensory indicators such as vapor color, odor, and visible reaction.

Odor is not a reliable detection method: odor thresholds vary widely between people, many toxic gases are odorless (carbon monoxide), and some materials cause olfactory fatigue or deaden the sense of smell.

CHEMTREC (1-800-424-9300) is the emergency response telephone number printed on US shipping papers; CANUTEC (1-613-996-6666) serves Canada.

Risk = probability of an adverse outcome multiplied by severity of consequence; the IC reduces risk by changing exposure (time, distance, shielding) rather than by changing the hazard itself.

Seven clues to the presence of hazardous materials: occupancy and location, container shapes, markings and colors, placards and labels, shipping papers, sensory clues, and criminal/terrorist indicators.

Isolation distances: initial cold zone for a small spill is at least 150 ft (50 m) in all directions; for a large spill, at least 300 ft (100 m); for fire involvement, ERG recommends initial isolation of 1,600 ft (500 m) in all directions.

Protective action distances in the ERG green pages are given for day and night conditions and for small and large spills; the greater distance governs the downwind protective action zone.

Vapor density greater than 1 means the gas is heavier than air and will travel along low ground and into basements, sewers, and confined spaces; vapor density less than 1 means it rises and disperses.

Specific gravity less than 1 means the liquid floats on water and spreads fire across the water surface; greater than 1 means it sinks and may enter storm drains or water intakes.

Flash point is the lowest temperature at which a liquid gives off enough vapor to ignite; a material is generally considered to have a flammable liquid hazard below 100 degrees F (37.8 degrees C) and a combustible liquid hazard at or above it.

Flammable range (LEL to UEL) widens with temperature; a reading on a combustible gas indicator is percent of the lower explosive limit, and readings above 10 percent LEL indicate an atmosphere approaching flammable conditions.

The first-arriving officer establishes command, transmits a size-up, and remains IC until command is formally transferred face-to-face with a briefing that covers incident conditions, actions taken, and assigned resources.

ICS organization expands only as needed: command, then command staff (safety officer, public information officer, liaison officer), then general staff (operations, planning, logistics, finance/administration).

Span of control is kept between three and seven subordinates, with five as the working target.

The incident action plan for the next operational period is produced by the planning section; the operations section chief directs tactical assignments within the current period.

Zone layout: hot zone (contamination reduction begins at its boundary), warm zone (decontamination corridor and access control), cold zone (command post, staging, medical, and media).

Unified command is used when multiple agencies with jurisdictional or functional authority share incident objectives; each agency retains its own authority but a single set of objectives is adopted.

The command post is located in the cold zone, upwind and uphill of the release, with a single entry/exit point and a written or electronic accountability system for all personnel in the hot zone.

Personnel accountability: every entry requires a minimum of two members in the hot zone with two outside (two-in/two-out), documented entry time, SCBA air check, and a planned exit time.

Defensive operations are conducted from outside the hot zone with no entry; offensive operations require trained, equipped personnel and a documented rescue or leak-control objective.

The ERG recommends evacuation over shelter-in-place when a release is prolonged, the material is highly toxic, or structures cannot be sealed; shelter-in-place is preferred for short-duration vapor releases and when evacuation would move people through the vapor cloud.

Do not extinguish a flammable gas fire at the source unless the fuel supply can be shut off; extinguishing without shutoff allows gas to accumulate and re-ignite explosively.

Water is not used as an extinguishing agent on water-reactive materials (DOT 4.3) or on reactive metals; use dry powder, dry sand, or appropriate class agent and prevent runoff contact.

For flammable liquid fires, foam blanket application rate and proportioning must match the fuel type: AFFF and fluoroprotein foams for hydrocarbon fuels, alcohol-resistant (AR-AFFF) foam for polar solvents such as ethanol and methanol.

Container failure indicators include bulging, discoloration, hissing or roaring vents, flame impingement on the vapor space, and pressure-relief device activation; withdraw and establish a large exclusion area.

A BLEVE occurs when a pressurized liquid container is heated above the boiling point of its contents and fails catastrophically; time to failure is unpredictable, so isolation must be established immediately.

Confinement (diking, damming, diversion, absorbents, sealing drains) is a defensive tactic that limits spread; containment (patches, plugs, overpack drums) keeps material inside its container.

Level A: fully encapsulating vapor-protective suit with SCBA worn inside, chemical-resistant gloves and boots; used when the highest level of skin, respiratory, and eye protection is required.

Level B: chemical-resistant splash suit with SCBA worn outside; provides the highest respiratory protection but less skin protection than Level A.

Level C: chemical-resistant suit with an air-purifying respirator; permitted only when the contaminant is known, its concentration is measured and below the canister limit, and the atmosphere has adequate oxygen (at least 19.5 percent).

Level D is work clothing only and provides no respiratory or chemical protection; it is not acceptable for any hazardous materials emergency entry.

Permeation is the movement of a chemical through a protective material at the molecular level; breakthrough time is measured by ASTM F739 and is the basis for suit selection.

Decontamination order (technical decon corridor): tool drop, gross wash, primary wash, rinse, secondary wash and rinse, then removal of the suit, with monitoring at the exit point.

All personnel and equipment leaving the hot zone pass through the decontamination corridor; runoff must be contained and never allowed to enter storm drains or waterways.

SCBA rated service time is 30, 45, or 60 minutes; air consumption rises with exertion, so entry teams plan exit at one-third to one-half of the rated cylinder capacity.

Absorption takes up a liquid into another material (vermiculite, clay, pads); adsorption collects material on the surface of a solid; both generate waste that must be containerized and disposed of properly.

Diking and damming use soil, sandbags, or commercial booms to hold liquid; diversion channels move product to a controlled collection area away from drains and water supplies.

Chlorine and other compressed gas leaks can sometimes be controlled by rolling a leaking cylinder so that gas rather than liquid escapes, reducing the release rate; this is a technician-level action.

Overpack drums (salvage drums) accept a leaking or damaged container up to 85 gallons capacity in a 55-gallon overpack; the original container must be upright and fit completely inside.

Plugging and patching (chlorine kits A, B, C; dome and flange patches) are technician-level leak-control methods and require the appropriate kit for the container type and valve configuration.

Flammable gas control includes shutting off the source, eliminating ignition sources, and ventilating with explosion-proof equipment; never ventilate into an area where gas can accumulate.

Solid materials that are dangerous when wet (DOT 4.3) are confined by excluding water and covering with dry material; water spray, foam, and wet absorbents must be avoided.

Vacuum trucks, portable pumps, and transfer operations require bonding and grounding when flammable liquids or combustible dusts are present to prevent static ignition.

Pre-incident plans identify fixed facilities, target hazards, occupancy types, stored quantities, container types, water supply, access routes, and evacuation zones for the community.

Facility emergency response plans under EPCRA require coordination with the local emergency planning committee (LEPC) and the local fire department, and must address notification, evacuation routes, and decontamination.

The emergency planning zone for extremely hazardous substances is established by the LEPC based on the substance, quantity, and vulnerable populations; it is used for notification and evacuation decisions.

Site-specific pre-plans include a site map with hydrant locations, a chemical inventory with SDSs, a staging area, a command post location, and an identified water supply for foam operations.

Tabletop and full-scale exercises test the plan; after-action reviews identify corrective actions that are tracked to completion, as required by NIMS and HSEEP guidance.

Mutual aid agreements and the incident management team activation process should be documented before an incident, including response times and resource capabilities.

Pre-plans are reviewed and updated when the facility changes its chemical inventory, process, or storage configuration, and at least annually.

Community notification systems (sirens, reverse 911, wireless emergency alerts) and shelter-in-place instructions should be pre-scripted and tested with the LEPC.

OSHA 29 CFR 1910.120 (HAZWOPER) requires a written emergency response plan, an incident command system, medical surveillance, and training: 40 hours for general site workers, 24 hours for occasional site visitors, and 8 hours annual refresher.

NFPA 472 (now consolidated into NFPA 470) defines responder competencies: awareness, operations, hazardous materials technician, incident commander, and specialist levels.

NFPA 1072 covers hazardous materials emergency response personnel professional qualifications, and NFPA 471 covers recommended practice for responding to hazardous materials incidents.

DOT 49 CFR 172 covers hazard communication, including shipping papers, marking, labeling, and placarding; 49 CFR 173 covers packaging requirements.

EPCRA (SARA Title III) requires facilities to report storage of hazardous chemicals above threshold planning quantities to the SEPA, LEPC, and local fire department, and requires community right-to-know reporting.

CERCLA (Superfund) establishes release reporting to the National Response Center (1-800-424-8802) for releases of reportable quantities; the NRC is the federal notification point for hazardous materials releases.

The incident commander is responsible for the safety of all personnel on scene; a safety officer is assigned when the incident complexity or number of responders warrants it.

Post-incident: personnel exposed above exposure limits require medical evaluation, exposure records are retained, and the after-action review documents the incident for training and liability purposes.