A Logistics Expert's Guide: Navigating the Shipping and Air Transport Classifications of Nitric Acid

—— A Focus on Shipping Nitric Acid from China

Introduction: The Concentration-Critical Hazard

In the complex world of international logistics, particularly for chemical and hazardous goods, precise classification is not just a formality—it's a legal and safety imperative. Nitric Acid (HNO₃) is a prime example of a common industrial chemical whose transportation identity is entirely defined by a single variable: its concentration. A slight variation in percentage can shift it from a routine corrosive to a strictly regulated substance with severe restrictions. This guide aims to clarify these critical thresholds for international buyers, procurement managers, and logistics professionals, ensuring safe, compliant, and efficient transport from China and beyond.

1. The Core Classification Framework: UN Numbers and Packing Groups

At the heart of nitric acid shipping are the UN (United Nations) Numbers and Packing Groups (PG), which dictate handling, packaging, and transport modality rules under global regulations like the IMDG Code (sea) and IATA DGR (air).

Key Classification Table:

2. Decoding the Critical Concentration Thresholds

Understanding the three key concentration benchmarks is essential for proper declaration and planning.

The 50% Threshold – Defining "Mixtures" and Oxidizing Properties:

For nitric acid in aqueous solution (mixtures with water), 50% concentration is the decisive line. At ≤50%, it is classified as UN 1796, PG II, with corrosive as the sole hazard, and is eligible for 1L Limited Quantity exemption. Above 50%, it retains UN 1796 but escalates to PG I and gains a 5.1 Oxidizer subsidiary risk, with no Limited Quantity permitted.

The 65% Threshold – The Oxidizer Mandate for Pure Acid:

For pure nitric acid (UN 2031), 65% is the critical marker for oxidizing properties. At concentrations of 65% and above, the acid must be assigned the subsidiary risk of Class 5.1 Oxidizer. Below 65%, it is classified as a Class 8 corrosive substance only. Crucial Note: Common reagent-grade nitric acid at ~68% concentration falls under this rule and carries the oxidizer hazard.

The 70% Threshold – Peak Hazard Level for UN 2031:

Within the UN 2031 series, concentration above 70% represents the highest hazard level, requiring the strictest Packing Group I and carrying both corrosive and oxidizing hazards, with no transport exemptions.

The Ultimate Restriction: Red Fuming Nitric Acid (UN 2032):

Nitric acid at concentrations ≥95% (often referred to as Red Fuming Nitric Acid) is the most hazardous variant. Classified under UN 2032, it is a Packing Group I substance with a triple threat: Corrosive (8) + Oxidizer (5.1) + Toxic (6.1). Due to its extreme reactivity and toxicity, it is strictly forbidden for transport by all commercial airlines and must be shipped via ocean freight or ground transport under the most stringent conditions.

3. Practical Implications for Shippers and Buyers

Air Transport Limitations: The presence of Oxidizer (5.1) and Toxic (6.1) hazards, especially for UN 2032, severely restricts or prohibits air transport. Most nitric acid above 50% concentration faces significant airline acceptance hurdles and requires full dangerous goods declaration.
Packaging and Documentation: The Packing Group (I, II, or III) directly determines the required packaging performance standards. An incorrect declaration (e.g., stating 68% acid without the 5.1 subsidiary risk) constitutes a serious regulatory violation.
Safety First: In case of a fire involving nitric acid, water should not be used as it can intensify the reaction. Approved extinguishing agents are carbon dioxide (CO₂) or dry chemical powder. For skin contact, the immediate response is copious flushing with water for at least 15 minutes.

Conclusion: Compliance Through Clarity

Successfully shipping nitric acid hinges on accurate knowledge of its concentration. The 50%, 65%, and 70% benchmarks are the linchpins for correct UN number assignment, hazard labeling, and transport mode selection. International buyers specifying nitric acid from suppliers must ensure the exact concentration is confirmed and properly declared on the Material Safety Data Sheet (MSDS/SDS) and shipping documentation to avoid costly delays, penalties, or safety incidents. When in doubt, always consult with a certified dangerous goods safety advisor (DGSA) or your freight forwarder's hazardous materials specialists.

Disclaimer: This guide provides general information based on IMDG Code and IATA DGR regulations. Always consult your freight forwarder and certified dangerous goods personnel for specific cargo requirements. Regulations are subject to change.

Contact with us now!

Have shipments want to order, or have more questions about shipping from China, why not contact with our sales now?

Get A Quote

UN Number	Concentration Criteria	Primary Hazard Class (IMO)	Packing Group	Subsidiary Risk(s)	Limited Quantity (Inner Packaging)
UN 2031	70%	Class 8 (Corrosive)	I	5.1 Oxidizer	Not permitted (0)
UN 2031	65% – 70%	Class 8 (Corrosive)	II	5.1 Oxidizer	1 L
UN 2031	< 65%	Class 8 (Corrosive)	II	None	1 L
UN 2032	≥ 95% (Red Fuming)	Class 8 (Corrosive)	I	5.1 Oxidizer + 6.1 Toxic	Not permitted (0)
UN 1796	50% (Mixtures)	Class 8 (Corrosive)	I	5.1 Oxidizer	Not permitted (0)
UN 1796	≤ 50% (Mixtures)	Class 8 (Corrosive)	II	None	1 L