HazMat Tool — substance information
Zinc dithionite or Zinc hydrosulfite
HMT May 2026Zinc dithionite or Zinc hydrosulfite
| Emergency Response Guide No. 171 |
Hazardous Materials Table
Source: 49 CFR §172 (2026/05)(3) Hazard Class9Miscellaneous hazardous materials |
(4) Identification number |
(5) Packing Group |
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(6) Labels None |
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(7) Special Provisions (§172.102)
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| IB8 | |
|---|---|
| IP3 | |
| T1 | |
| TP33 |
(8) Packing Authorizations (§173.***) 
| (8A) Exceptions | 155 | see 49 CFR §173.155 |
|---|---|---|
| (8B) Non-bulk | 204 | see 49 CFR §173.204 |
| (8C) Bulk | 240 | see 49 CFR §173.240 |
(9) Quantity Limits 
| (9A) Passenger aircraft/rail | 100 kg |
|---|---|
| (9B) Cargo aircraft only | 200 kg |
(10) Vessel stowage 
| (10A) Location | |
|---|---|
| (10B) Other |
Segregation chart for load, transport, and storage
This chart shows whether loading, transport, or storage with other hazard classes is permitted, prohibited, or restricted. Based on 49 CFR §177.848.
No compatibility information for class 9 in 49 CFR §177.848 included.
Scope & sources (important)Click to show CFR references
This check evaluates segregation per 49 CFR §177.848. Additional loading/unloading and handling requirements may still apply; see 49 CFR §177 Subpart B (Loading and Unloading):
- §177.834 - General requirements
- §177.835 - Class 1 materials
- §177.837 - Class 3 materials
- §177.838 - Class 4 (flammable solid) materials, Class 5 (oxidizing) materials, and Division 4.2 (pyroforic liquid) materials
- §177.839 - Class 8 (corrosive) materials
- §177.840 - Class 2 (gases) materials
- §177.841 - Division 6.1 and Division 2.3 materials
- §177.842 - Class 7 (radioactive) material
- §177.843 - Contamination of vehicles