49 CFR 172 Special Provision 21 (Numeric Codes)
These provisions are multi-modal and apply to bulk and non-bulk packagings.
| Code | 21 |
|---|---|
| Description | This material must be stabilized by appropriate means (e.g., addition of chemical inhibitor, purging to remove oxygen) to prevent dangerous polymerization (see §173.21(f) of this subchapter). |
| HazMat with this Code |