# All insulated cargo tanks, except MC 330, MC 331, MC 338 — How often hazmat cylinders, cargo tanks, IBCs and portable tanks must be retested

For All insulated cargo tanks, except MC 330, MC 331, MC 338, test or inspection is Internal Visual Inspection; interval is 1 year; regulation section is 49 CFR § 180.407, recorded from its source on 2026-08-10.

- **Container specification:** All insulated cargo tanks, except MC 330, MC 331, MC 338 _(verified: appears in the quote below)_
- **Test or inspection:** Internal Visual Inspection _(our reading, not quoted from the source)_
- **Interval:** 1 year. _(verified: appears in the quote below)_
- **Regulation section:** 49 CFR § 180.407 _(verified: appears in the quote below)_

## What the source says

> Internal Visual Inspection: | | | All insulated cargo tanks , except MC 330, MC 331, MC 338 (see Note 4) | September 1, 1991 | 1 year.

## Source

- https://www.law.cornell.edu/cfr/text/49/180.407

Last verified: 2026-08-10. Review by: 2027-08-10.
Part of [How often hazmat cylinders, cargo tanks, IBCs and portable tanks must be retested](https://referencesource.org/hazmat-container-retest-intervals/).