What transport class is thiourea dioxide, and what does export involve?

Direct answer

Thiourea dioxide is a UN Class 4.2 self-heating substance, UN 3341, packing group II, and is not classified as a marine pollutant. Export requires dangerous-goods declaration, compliant packaging and shipping documentation.

Transport classification

Packing and labelling

Use UN-approved packaging with the Class 4.2 self-heating label, and state UN 3341, Class 4.2 and packing group II on the transport documents.

The key difference from hydrosulfite

Sodium hydrosulfite (sodium dithionite, UN 1384) is a water-reactive substance releasing flammable gas: it needs temperature- and humidity-controlled storage, cannot be loaded in rain and requires airtight packaging. Thiourea dioxide is self-heating, so transport and storage restrictions are far fewer - one of the practical reasons mills switch.

Storage requirements

Sealed, cool and dry, not above 25 °C, away from oxidants, metal salts and alkalis; shelf life at least 6 months.

Common export questions

• Is dangerous-goods certification needed? Yes, as a Class 4.2 substance. We can supply UN-approved packaging, IMDG-compliant sea-freight documentation and the corresponding test reports.
• Can it be shipped by air? IATA rules apply and actual acceptance depends on the carrier; confirm in advance.

Sources

Section 14 (Transport information) of our product SDS.