Class 5 (Oxidizing Substances & Organic Peroxides) & Class 6 (Toxic & Infectious Substances)

Class 5 (Oxidizing Substances & Organic Peroxides) & Class 6 (Toxic & Infectious Substances)

Chemicals capable of releasing oxygen to accelerate fires, thermally decomposing violently, or posing lethal biological/toxic hazards present severe risks in aviation. Class 5 and Class 6 govern these active chemical and biological hazards under IATA DGR criteria.

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Hazard Class 5: Oxidizing Substances & Organic Peroxides

Class 5 is divided into two distinct divisions based on chemical structure and reaction kinetics:

• Division 5.1: Oxidizing Substances — Substances which, while in themselves not necessarily combustible, may, generally by yielding oxygen, cause, or contribute to, the combustion of other material.
• Division 5.2: Organic Peroxides — Organic substances which contain the bivalent $-O-O-$ structure and may be considered derivatives of hydrogen peroxide ($H_2O_2$), where one or both hydrogen atoms have been replaced by organic radicals.

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Division 5.1: Oxidizing Substances Classification & Packing Groups

Division 5.1 solid and liquid oxidizers are evaluated by measuring the rate of burning when mixed with combustible materials (such as dried cellulose) relative to reference oxidizers (Potassium Bromate or Perchloric Acid).

Solid Oxidizers (Mean Burning Time Test)

• Packing Group I: Any substance which, in a 4:1 or 1:1 sample-to-cellulose ratio by mass, exhibits a mean burning time less than that of a 3:2 potassium bromate-to-cellulose mixture. Example: Oxidizing solid, n.o.s. (UN 1479) where the entry is assigned PG I.
• Packing Group II: Any substance which exhibits a mean burning time equal to or less than that of a 2:3 potassium bromate-to-cellulose mixture, and PG I criteria are not met. Examples: Potassium chlorate (UN 1485), Sodium chlorate (UN 1495). Sodium nitrate (UN 1498) sits one step lower, at PG III.
• Packing Group III: Any substance which exhibits a mean burning time equal to or less than that of a 3:7 potassium bromate-to-cellulose mixture, and PG I/II criteria are not met.

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Division 5.2: Organic Peroxides (Types A through G)

Organic peroxides are thermally unstable compounds liable to undergo self-accelerating exothermic decomposition. They can ignite combustibly, detonate, deflagrate, or react dangerously with other substances. Organic peroxides are assigned to one of seven types (Types A through G):

                                    ORGANIC PEROXIDE TYPES (A to G)
  ┌───────────────┬───────────────┬───────────────┬───────────────┬───────────────┬───────────────┬───────────────┐
  │    TYPE A     │    TYPE B     │    TYPE C     │    TYPE D     │    TYPE E     │    TYPE F     │    TYPE G     │
  ├───────────────┼───────────────┼───────────────┼───────────────┼───────────────┼───────────────┼───────────────┤
  │ Can detonate  │ Can detonate  │ Can detonate  │ Detonates     │ Neither       │ Neither       │ Thermally     │
  │/ deflagrate   │/ deflagrate   │/ deflagrate   │ partially or  │ detonates nor │ detonates nor │ stable;       │
  │ rapidly as    │ slowly, but   │ slowly, but   │ deflagrates   │ deflagrates;  │ deflagrates;  │ no explosive  │
  │ packaged.     │ safe in       │ cannot        │ slowly; low   │ low effect    │ low/no power; │ power.        │
  │               │ packages.     │ detonate.     │ heat effect.  │ when heated.  │ packaged ok.  │               │
  ├───────────────┼───────────────┼───────────────┼───────────────┼───────────────┼───────────────┼───────────────┤
  │  FORBIDDEN    │ Permitted with│ Permitted on  │ Permitted on  │ Permitted on  │ Permitted on  │ Exempt from   │
  │ FOR TRANSPORT │ CAO / Max Qty │ Aircraft      │ Aircraft      │ Aircraft      │ Aircraft      │ Division 5.2  │
  └───────────────┴───────────────┴───────────────┴───────────────┴───────────────┴───────────────┴───────────────┘

Crucial Air Transport Restrictions for Division 5.2

1. Type A Organic Peroxides are FORBIDDEN FOR TRANSPORT on any aircraft.
2. Temperature Control Requirement: If an organic peroxide has a Self-Accelerating Decomposition Temperature (SADT) of 50°C (122°F) or less, it requires temperature control during transport. Under IATA DGR provisions, all dangerous goods requiring temperature control are strictly FORBIDDEN FOR AIR TRANSPORT.

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Hazard Class 6: Toxic & Infectious Substances

Class 6 is divided into two sub-divisions:

• Division 6.1: Toxic Substances
• Division 6.2: Infectious Substances

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Division 6.1: Toxic Substances Toxicity Criteria

Division 6.1 covers substances liable to cause death or serious injury or to harm human health if swallowed, inhaled, or brought into contact with skin.

Toxicity Thresholds for Packing Group Assignment

Grouping is based on acute animal testing data expressed as $LD_{50}$ (lethal dose for 50% of test population, in mg/kg body weight) or $LC_{50}$ (lethal concentration for 50% of test population, in mg/L or mL/m³):

Inhalation Toxicity of Vapors (Liquid Volatility Ratio)

For liquid substances emitting toxic vapors, Packing Group assignment utilizes both the acute inhalation toxicity ($LC_{50}$) and the saturated vapor concentration ($V$) of the liquid at $20^\circ\text{C}$ in $\text{mL/m}^3$:

• Packing Group I: $V \ge 10 \times LC_{50}$ AND $LC_{50} \le 1000\text{ mL/m}^3$.
• Packing Group II: $V \ge LC_{50}$ AND $LC_{50} \le 3000\text{ mL/m}^3$ (and PG I criteria are not met).
• Packing Group III: $V \ge \frac{1}{5} LC_{50}$ AND $LC_{50} \le 5000\text{ mL/m}^3$ (and PG I/II criteria are not met).

                    INHALATION VAPOR TOXICITY NOMOGRAM
   Vapor Conc (V) 
        ▲
        │    PG I Zone  (V ≥ 10 × LC50  AND  LC50 ≤ 1000 ppm)
        │   ┌──────────────────────┐
        │   │                      │
        │   │   PG II Zone         │ (V ≥ LC50  AND  LC50 ≤ 3000 ppm)
        │   │  ┌───────────────────┴─────────────┐
        │   │  │                                 │   PG III Zone
        │   │  │   PG III Zone                   │ (V ≥ 1/5 LC50 AND LC50 ≤ 5000 ppm)
        └───┴──┴─────────────────────────────────┴────────────────────────► LC50 (ppm)

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Division 6.2: Infectious Substances

Division 6.2 covers substances known or reasonably expected to contain pathogens (microorganisms including bacteria, viruses, rickettsiae, parasites, fungi, or prions).

Infectious substances are categorized into Category A or Category B:

Category A Infectious Substances

An infectious substance transported in a form that, when exposure occurs, is capable of causing permanent disability, life-threatening or fatal disease in otherwise healthy humans or animals.

• UN 2814: Infectious substance, affecting humans. Examples: Ebola virus, Lassa virus, Marburg virus, Anthrax spores (Bacillus anthracis).
• UN 2900: Infectious substance, affecting animals only. Examples: Foot and mouth disease virus, African swine fever virus.
• Packaging: Requires UN specification triple packaging meeting Packing Instruction 620 (capable of passing drop tests from 9 meters and puncture tests).

Category B Infectious Substances

An infectious substance that does not meet the criteria for inclusion in Category A.

• UN 3373: Biological Substance, Category B. Examples: Routine COVID-19 diagnostic swabs, Hepatitis B blood diagnostic samples, Dengue virus diagnostic specimens.
• Packaging: Must be packaged in compliance with Packing Instruction 650 (triple packaging system, leakproof primary and secondary receptacles, 95 kPa pressure differential test rating). Does not require a Shipper's Declaration if compliant.