It is something of a puzzle that molasses seems to be a leak hazard.

Anyone who's tried to screw the lid off the jar, when the last user left a little sticky on the rim, should be able to attest that in general, the molasses doesn't want to get out!"

The recent Hawaiian leak doesn't suggest anything mysterious. Hundred-plus year old plumbing, unmaintained, and it didn't work when something got loose inside.

Unfortunately, the "plumbing" involved is quite representative of many municipal systems like water, storm drain, and sewage systems in the US (and probably in a lot of "elsewheres") that is long overdue for rehabilitation that those systems are unlikely to get.

Lots of our plumbing is even older (and less well maintained) than our crumbling bridges.

John