The ballot drop boxes in Washington and Oregon both have fire suppression systems that are designed to activate when the temperature inside reaches a certain point, coating ballots inside with a fire-suppressing powder.
For unknown reasons, the system failed to prevent the destruction of hundreds of ballots in Vancouver, just across the Columbia River from Portland.
I was actually surprised that more ballot boxes weren’t being firebombed; I didn’t know they had fire suppression systems and am glad to hear it (and also slightly shocked that they’re necessary; chalk another point on the board for we’ve failed as a society and as a species).