# DOT 4BW — How often hazmat cylinders, cargo tanks, IBCs and portable tanks must be retested

For DOT 4BW, test or inspection is External visual inspection; interval is at five-year intervals after the first inspection; condition or service qualifier is Alkali metal alloys, liquid, n.o.s., Alkali metal dispersions or Alkaline earth metal dispersions, Potassium, Potassium Sodium alloys and Sodium that are commercially free of corroding components; regulation section is 49 CFR § 180.209, recorded from its source on 2026-08-06.

- **Container specification:** DOT 4BW _(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:** Alkali metal alloys, liquid, n.o.s., Alkali metal dispersions or Alkaline earth metal dispersions, Potassium, Potassium Sodium alloys and Sodium that are commercially free of 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 4BW | Alkali metal alloys, liquid , <https://www.law.cornell.edu/definitions/index.php?width=840&height=800&iframe=true&def_id=ce9675606a240905d07508526a234d2a&term_occur=999&term_src=Title:49:Subtitle:B:Chapter:I:Subchapter:C:Part:180:Subpart:C:180.209> n.o.s ., Alkali metal dispersions or Alkaline earth metal dispersions, Potassium , Potassium Sodium alloys and Sodium that are commercially free of 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/).