DG Class 8: Corrosive Substances – ADG Code, Chapter 2.8

Published: September 5, 2025| Last Updated: September 5, 2025

There are 9 dangerous goods classes in total, as set by the Australian Dangerous Goods Code, which is developed and maintained by the National Transport Commission (NTC). This article covers the 8th dangerous goods class, referred to as Dangerous Goods (DG) Class 8.

The information from this article was obtained from Chapter 2.8 – Corrosive Substances on the latest version of the ADG Code. This guide provides up-to-date, helpful information on DG Class 8, but is not a replacement for the official documentation, which can be accessed from the National Transport Commission’s (NTC’s) website at the following address: https://www.ntc.gov.au/codes-and-guidelines/australian-dangerous-goods-code

Dangerous Goods (DG) Class 8 covers substances that, through chemical action, can cause severe damage upon contact with living tissue or can materially damage or destroy other goods and transport vehicles in the event of a leak. Known as corrosives, these materials range from common industrial acids and bases to specific solids that can damage metals. Here’s what logistics providers, shipping professionals, and SMEs need to know about properly classifying DG Class 8: Corrosive Substances.

Overview of DG Class 8 Hazards

Unlike other classes that might focus on a single property like flammability, Class 8 classification is based on a substance’s destructive effect on surfaces. The primary hazards are:

Skin Corrosion: The substance causes irreversible damage to the skin—specifically, visible necrosis that penetrates through the epidermis and into the dermis. The classification is based on how quickly this damage occurs.
Metal Corrosion: A substance that may not be corrosive to skin can still be classified as Class 8 if it has a high corrosion rate on either steel or aluminum surfaces (exceeding 6.25 mm per year at a test temperature of 55 °C). This is a critical criterion for many industrial liquids.

Detailed Breakdown: Packing Groups I, II, & III

The ADG Code divides Class 8 substances into three Packing Groups (PG) according to their degree of danger. This assignment is critical, as it dictates the required strength and type of packaging, as well as handling and transport regulations.

Packing Group I (High Danger)

These are the most dangerous corrosive substances, capable of causing rapid destruction.

Classification Criteria: Substances that cause irreversible skin damage within an observation period of 60 minutes following an exposure time of 3 minutes or less.
Common Examples:
- UN 1830: SULFURIC ACID (with more than 51% acid)
- UN 1796: NITRATING ACID MIXTURES
- UN 1744: BROMINE or BROMINE SOLUTIONS

Packing Group II (Medium Danger)

These substances present a medium-level corrosive hazard and have less aggressive reaction times than PG I.

Classification Criteria: Substances that cause irreversible skin damage within an observation period of 14 days following an exposure time of more than 3 minutes but no more than 60 minutes.
Key Compliance Note: In the absence of other data, liquid waste substances with a pH of less than 2.0 or greater than 12.5 are typically assigned to PG II.
Common Examples:
- UN 1789: HYDROCHLORIC ACID
- UN 1824: SODIUM HYDROXIDE SOLUTION (Caustic Soda)
- UN 3264: CORROSIVE LIQUID, ACIDIC, INORGANIC, N.O.S.

Packing Group III (Minor Danger)

This is the least dangerous category, encompassing substances that are slower-acting or are primarily a threat to materials rather than skin.

Classification Criteria: Substances that either:
1. Cause irreversible skin damage within an observation period of 14 days following an exposure time of more than 60 minutes but no more than 4 hours; OR
2. Are shown to corrode steel or aluminum surfaces at a rate exceeding 6.25 mm per year.
Common Examples:
- UN 2790: ACETIC ACID SOLUTION (with 10-80% acid)
- UN 1760: CORROSIVE LIQUID, N.O.S. (Not Otherwise Specified)
- UN 3266: CORROSIVE LIQUID, BASIC, ORGANIC, N.O.S.

How Are Corrosive Mixtures Classified?

For mixtures, the ADG Code outlines a clear, tiered approach to determine the correct Packing Group.

Testing Data: The preferred method is to use test data on the mixture itself.
Bridging Principles: If the mixture hasn’t been tested, you can use data from similar tested mixtures. This allows for logical classifications based on principles like:
- Dilution: Adding a non-corrosive diluent generally doesn’t change the PG.
- Batching: Different production batches from the same manufacturer are assumed to be equivalent.
- Concentration: A concentrated version of a PG I mixture is also assigned to PG I.
Calculation Method: As a final option, if no test or bridging data is available, a calculation can be performed based on the concentration of the classified corrosive ingredients within the mixture. The classification is determined by whether the sum of ingredient concentrations exceeds specific thresholds for each packing group.

Practical Takeaways for Your Business

Classification is Your Responsibility: The consignor is legally responsible for correctly classifying, packaging, and documenting corrosive substances. Never assume a product’s classification without data.
Packing Group is Crucial: The assigned Packing Group (I, II, or III) directly impacts all transport requirements. A PG I substance requires much more stringent packaging and handling than a PG III substance.
Consider Both Skin and Metal Corrosion: Remember that a product can be a Class 8 dangerous good due to its effect on metal, even if it has a low skin-corrosion hazard. Always check for both criteria.
When in Doubt, Refer to the Code: This guide is a summary. The official ADG Code is the ultimate source for detailed compliance requirements and should always be consulted. It is available from the NTC at: https://www.ntc.gov.au/codes-and-guidelines/australian-dangerous-goods-code.

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