Special provision 522
ADR 2025 — special provision (SP) 522, Chapter 3.3.
UN No. 1873 perchloric acid aqueous solution with more than 50 % but not more than 72 % pure acid, by mass are substances of Class 5.1. Perchloric acid solutions containing more than 72 % pure acid, by mass, or mixtures of perchloric acid with any liquid other than water, are not to be accepted for carriage.