Yep, airships aren’t overpressurized like a balloon - any leak will be extremely slow, as the heavier ambient air gradually displaces the helium inside the airship through whatever hole might be created. As I understand it, one of the big maintenance issues they have is even finding the holes from normal wear and tear. The usual failure scenarios involve storms with huge pressure changes.

One thing that surprised me in the article - I had no idea magma could be acidic!