# MC 330 and MC 331 — How often hazmat cylinders, cargo tanks, IBCs and portable tanks must be retested For MC 330 and MC 331, test or inspection is Pressure Test; interval is 2 years; condition or service qualifier is in chlorine service; regulation section is 49 CFR § 180.407, recorded from its source on 2026-08-10. - **Container specification:** MC 330 and MC 331 _(verified: appears in the quote below)_ - **Test or inspection:** Pressure Test _(our reading, not quoted from the source)_ - **Interval:** 2 years. _(verified: appears in the quote below)_ - **Condition or service qualifier:** in chlorine service _(verified: appears in the quote below)_ - **Regulation section:** 49 CFR § 180.407 _(verified: appears in the quote below)_ ## What the source says > MC 330 and MC 331 cargo tanks in chlorine service | September 1, 1992 | 2 years. ## 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/).