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Hazmat Class 8 is the U.S. Department of Transportation hazard class for corrosive materials: liquids or solids that cause irreversible damage to human skin on contact, or that corrode steel or aluminum at a severe rate. Class 8 shipments carry the CORROSIVE label and a packing group (I, II or III) shown on the shipping paper. This page is general regulatory information for lab and clinic staff, not legal advice or a substitute for trained, certified hazmat shipping personnel.
Definition and scope
Under 49 CFR 173.136(a), a Class 8 (corrosive) material is a liquid or solid that causes irreversible damage to human skin at the site of contact within a specified period of exposure. A liquid, or a solid that may become liquid during transport, also falls in Class 8 if it corrodes steel or aluminum at the severe rate set in 173.137(c)(2). Where practical, the regulation directs classifiers to use the in vitro methods in 173.137 or historical data, and 173.136(b) lets PHMSA revise a classification when human experience or other data show the hazard is greater or less than the test indicates.
This page covers the shipping side of Class 8. The skin-corrosion test detail is on our corrosive fluids guide; the equivalent page for flammable liquids is Hazmat Class 3. Class 8 is the DOT term; internationally the same class number appears in the IMDG Code classes.
How Class 8 is used in practice
Packing groups
A packing group grades the degree of danger within the class. Under 173.137, Class 8 materials are assigned as follows:
- Packing Group I: irreversible skin damage after an exposure of up to 3 minutes, observed for up to 60 minutes.
- Packing Group II: damage after more than 3 minutes and up to 60 minutes of exposure, observed for up to 14 days.
- Packing Group III: damage after more than 60 minutes and up to 4 hours of exposure, observed for up to 14 days; also materials that corrode steel or aluminum faster than 6.25 mm per year at 55 °C.
Label versus placard
Two different markings are often confused. The CORROSIVE label goes on packages. Under 49 CFR 172.442, besides the general label rules of 172.407, its background is white in the top half and black in the lower half. The placard goes on transport vehicles, freight containers and similar units, and for Class 8 it is the CORROSIVE placard specified in 172.558.
Class 8 is a Table 2 category in 172.504(e). Under 172.504(c), when Table 2 materials move by highway or rail, no placard is required on a transport vehicle or freight container holding less than 454 kg (1,001 pounds) aggregate gross weight of Table 2 materials. That exception does not apply to bulk packagings or to materials subject to 172.505. The exception is a weight threshold on the whole load, not a property of the chemical.
Where it matters for labs, clinics and supply decisions
Whether a given product is Class 8 is not decided by its name alone; it comes from the Hazardous Materials Table entry and the classification rules above. Our guide to hazmat shipping for medical supplies covers the wider picture, and shipping papers under 49 CFR covers the documentation that records the class and packing group.
Class 8 questions, and where each answer comes from
| Question | Where the answer comes from |
|---|---|
| Is the material Class 8, and which packing group? | Hazardous Materials Table entry and 173.136 / 173.137 (skin-corrosion or steel/aluminum corrosion data) |
| Which label goes on the package? | CORROSIVE label, 172.442, with the general label rules in 172.407 |
| Does the vehicle or freight container need a placard? | 172.504: Table 2 category; the 454 kg (1,001 lb) aggregate exception does not cover bulk packagings or 172.505 materials |
| Where is the class recorded? | The shipping paper (see our shipping papers guide) |
Common misunderstandings
- Corrosive does not only mean acid. The definition in 173.136 is about irreversible skin damage or severe metal corrosion, not about pH wording.
- Class 8 and Class 9 are separate classes. See Class 9 dangerous goods.
- Under 454 kg does not mean no hazmat rules. The 454 kg figure only relaxes vehicle placarding for Table 2 materials; it does not remove the label or shipping paper requirements.
- Label and placard are not the same thing. The label marks a package; the placard marks the vehicle or container.
FAQ
What is hazmat Class 8?
Class 8 is the DOT hazard class for corrosive materials: liquids or solids that irreversibly damage human skin on contact, or corrode steel or aluminum at a severe rate (49 CFR 173.136).
What does the Class 8 label look like?
It is the CORROSIVE label of 49 CFR 172.442, with a background that is white in the top half and black in the lower half.
Do I need a placard to ship a Class 8 package?
Placarding applies to vehicles, freight containers and similar units, not to individual packages. For Table 2 materials such as Class 8, 172.504(c) removes the placard requirement below 454 kg (1,001 lb) aggregate gross weight, except for bulk packagings and 172.505 materials.
Sources
- 49 CFR 173.136, Class 8: Definitions, eCFR, read 2026-11-08: ecfr.gov/current/title-49/section-173.136
- 49 CFR 173.137, Class 8: Assignment of packing group, as summarized on our corrosive fluids guide.
- 49 CFR 172.442, CORROSIVE label, read 2026-11-08: ecfr.gov/current/title-49/section-172.442
- 49 CFR 172.504, General placarding requirements, read 2026-11-08: ecfr.gov/current/title-49/section-172.504
