# DOT 3A, 3A480X, or 4AA480 — How often hazmat cylinders, cargo tanks, IBCs and portable tanks must be retested

For DOT 3A, 3A480X, or 4AA480, test or inspection is Periodic requalification; interval is every 10 years instead of every five years; condition or service qualifier is used exclusively for anhydrous ammonia, commercially free from corroding components, and protected externally by a suitable corrosion-resistant coating (such as paint); regulation section is 49 CFR § 180.209, recorded from its source on 2026-08-06.

- **Container specification:** DOT 3A, 3A480X, or 4AA480 _(verified: appears in the quote below)_
- **Test or inspection:** Periodic requalification _(our reading, not quoted from the source)_
- **Interval:** every 10 years instead of every five years _(verified: appears in the quote below)_
- **Condition or service qualifier:** used exclusively for anhydrous ammonia, commercially free from corroding components, and protected externally by a suitable corrosion-resistant coating (such as paint) _(verified: appears in the quote below)_
- **Regulation section:** 49 CFR § 180.209 _(verified: appears in the quote below)_

## What the source says

> A cylinder conforming to specification DOT 3A, 3A480X, or 4AA480 used exclusively for anhydrous ammonia, commercially free from corroding components, and protected externally by a suitable corrosion-resistant coating (such as paint) may be requalified every 10 years instead of every five years.

## Source

- https://www.law.cornell.edu/cfr/text/49/180.209

Last verified: 2026-08-06. Review by: 2027-08-06.
Part of [How often hazmat cylinders, cargo tanks, IBCs and portable tanks must be retested](https://referencesource.org/hazmat-container-retest-intervals/).