Class 8 — Corrosives
Substances that destroy skin tissue or corrode steel or aluminium at a defined rate.
What actually falls under Corrosives
A substance qualifies as Class 8 by either of two independent tests: full-thickness destruction of skin tissue within a specified exposure and observation window, or a corrosion rate against steel or aluminium above the threshold in 49 CFR 173.136. That second test catches products most sellers wouldn't intuitively call corrosive — a rust remover or battery electrolyte can be Class 8 purely on metal-corrosion grounds even if it's mild on skin. Ten entries are encoded, covering the products that generate the most classification requests in this class: drain cleaner and soap-making lye (sodium hydroxide, split between solid and solution entries with different UN numbers), pool and laundry bleach (hypochlorite), descalers (hydrochloric and sulfuric acid), and lead-acid battery electrolyte. Concentration is the recurring trap: a dilute household cleaner and a concentrated industrial version of the same active ingredient frequently sit on different sides of the regulatory threshold entirely.
Carrier acceptance
The published default for this class. A UN-specific rule can override it — lithium batteries and dry ice are both Class 9 and are treated quite differently.
| Carrier | Ground | Air | Position |
|---|---|---|---|
| UPS | contract required | contract required | Corrosives accepted under the hazmat agreement; limited quantity ground is available for retail packs. |
| FedEx | contract required | contract required | Corrosives require dangerous goods approval; limited quantity moves on FedEx Ground. |
| USPS | restricted | prohibited | Corrosives in packing groups II and III are mailable by surface only as a limited quantity; packing group I is non-mailable. |
| Amazon FBA | review required | restricted | Corrosives in packing groups II and III accepted after review; packing group I is not accepted. |
Carrier positions encode each carrier's published default as of the ruleset date. Tariffs change more often than regulations, and a contracted shipper may hold different terms — confirm against the carrier's current guide before the first shipment of a new item.
Encoded entries (10)
| UN | Proper shipping name | Class | PG | Labels | Air |
|---|---|---|---|---|---|
| UN1791 | Hypochlorite solution | 8 | II/III — derived | CORROSIVE | pax limited·cargo permitted |
| UN1824 | Sodium hydroxide solution | 8 | II/III — derived | CORROSIVE | pax limited·cargo permitted |
| UN1823 | Sodium hydroxide, solid | 8 | II | CORROSIVE | pax limited·cargo permitted |
| UN1789 | Hydrochloric acid | 8 | II/III — derived | CORROSIVE | pax limited·cargo permitted |
| UN1830 | Sulfuric acid with more than 51% acid | 8 | II | CORROSIVE | pax limited·cargo permitted |
| UN2796 | Battery fluid, acid | 8 | II | CORROSIVE | pax limited·cargo permitted |
| UN2794 | Batteries, wet, filled with acid, electric storage | 8 | none | CORROSIVE | pax limited·cargo permitted |
| UN2800 | Batteries, wet, non-spillable, electric storage | 8 | none | CORROSIVE | pax limited·cargo permitted |
| UN1760 | Corrosive liquid, n.o.s. | 8 | I/II/III — derived | CORROSIVE | pax limited·cargo permitted |
| UN2809 | Mercury(subsidiary 6.1) | 8 | III | CORROSIVE, TOXIC | pax forbidden·cargo limited |
Classify a specific product in this class
The class alone does not give you a shipping paper. Send the actual product to POST /api/classify and you get the UN number, the proper shipping name, the packing group and every carrier position for that specific item.
Carrier rules for this class
Each carrier page sets out its ground and air position for all nine classes.
Other hazard classes
- Class 1 — Explosives
- Division 2.1 — Flammable gas
- Division 2.2 — Non-flammable, non-toxic gas
- Division 2.3 — Toxic gas
- Class 3 — Flammable liquids
- Division 4.1 — Flammable solids
- Division 4.2 — Spontaneously combustible
- Division 4.3 — Dangerous when wet
- Division 5.1 — Oxidizers
- Division 5.2 — Organic peroxides
- Division 6.1 — Toxic substances
- Division 6.2 — Infectious substances
- Class 7 — Radioactive material
- Class 9 — Miscellaneous
Guides
Questions
- What is Class 8 — Corrosives?
- Substances that destroy skin tissue or corrode steel or aluminium at a defined rate.
- Does Class 8 — Corrosives have a packing group?
- Yes for most entries. Packing group I is the highest danger, II medium, III low. Where an entry's packing group depends on a measured property (a flash point for Class 3, a concentration for Class 8), Classify7 asks for that figure rather than assuming one.
- Can I ship Class 8 — Corrosives by air?
- UPS: contract required; FedEx: contract required; USPS: prohibited; Amazon FBA: restricted. These are published carrier defaults, not regulatory limits — a contracted shipper may hold different terms, and the regulation may permit what the carrier declines.