The DOT regulation at $49$ C$.$F$.$R$.$ $$173\mathrm{.}181$ requires shippers and carriers to transport pyrophoric liquids in specific types of packaging such as metal cans and steel drums that remain sealed by means of friction$-$free closures until use. What is the most likely reason that DOT requires friction$-$free closures on the packaging used for the domestic shipment of triethylaluminum?