# DOT 3A, DOT 3AA, DOT 3B, DOT 4B, DOT 4BA, DOT 4BW, DOT 4E — How often hazmat cylinders, cargo tanks, IBCs and portable tanks must be retested

For DOT 3A, DOT 3AA, DOT 3B, DOT 4B, DOT 4BA, DOT 4BW, DOT 4E, test or inspection is External visual inspection; interval is at five-year intervals after the first inspection; condition or service qualifier is Propylene that is commercially free from corroding components; regulation section is 49 CFR § 180.209, recorded from its source on 2026-08-06.

- **Container specification:** DOT 3A, DOT 3AA, DOT 3B, DOT 4B, DOT 4BA, DOT 4BW, DOT 4E _(verified: appears in the quote below)_
- **Test or inspection:** External visual inspection _(our reading, not quoted from the source)_
- **Interval:** at five-year intervals after the first inspection _(verified: appears in the quote below)_
- **Condition or service qualifier:** Propylene that is commercially free from corroding components _(verified: appears in the quote below)_
- **Regulation section:** 49 CFR § 180.209 _(verified: appears in the quote below)_

## What the source says

> DOT 3A, DOT 3AA, DOT 3B, DOT 4B, DOT 4BA, DOT 4BW, DOT 4E | Propylene that is commercially free from corroding components.

## 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/).