# Hazardous materials — aircraft and rail quantity limits (HMT Columns 9A/9B) — Postal shipping restrictions by item category

For Hazardous materials, item category is Hazardous materials — aircraft and rail quantity limits (HMT Columns 9A/9B); carrier is US DOT (49 CFR, air and rail); restriction type is restricted; scope is passenger-carrying aircraft, passenger rail car, cargo aircraft; conditions is Columns 9A and 9B specify the maximum quantities per package by passenger-carrying aircraft or rail car (9A) or by cargo aircraft only (9B); 'Forbidden' means the material may not be transported in that mode, recorded from its source on 2026-08-10.

- **Item category:** Hazardous materials — aircraft and rail quantity limits (HMT Columns 9A/9B) _(verified: appears in the quote below)_
- **Carrier:** US DOT (49 CFR, air and rail) _(our reading, not quoted from the source)_
- **Restriction type:** restricted _(our reading, not quoted from the source)_
- **Scope:** passenger-carrying aircraft, passenger rail car, cargo aircraft _(our reading, not quoted from the source)_
- **Conditions:** Columns 9A and 9B specify the maximum quantities per package by passenger-carrying aircraft or rail car (9A) or by cargo aircraft only (9B); 'Forbidden' means the material may not be transported in that mode. _(verified: appears in the quote below)_

## What the source says

> Columns 9A and 9B specify the maximum quantities that may be offered for transportation in one package by passenger-carrying aircraft or passenger-carrying rail car (Column 9A) or by cargo aircraft only (Column 9B)

## Source

- https://www.ecfr.gov/current/title-49/subtitle-B/chapter-I/subchapter-C/part-172/subpart-B

Last verified: 2026-08-10. Review by: 2027-08-10.
Part of [Postal shipping restrictions by item category](https://referencesource.org/shipping-restrictions-by-class/).