In article , Mike Andrews
writes

Some years ago I wandered into one of the design labs to ask some questions
about a new thingy we were doing.

On a bench was a metal trash can with wires leading to a power supply,
thermometer, and a chart recorder.

[snip]

We got off the floor and looked up to the acoustical ceiling where there
was capacitor pieces and an alligator clip embedded therein.

When the guy running the test said "Maybe we had better rethink this
design", I decided to go back to my lab and come back on a better day.

We continued to use tantalums (aerospace), but there were a lot more
explosions in the lab to make sure they didn't happen on the shipped
product.
Read the data books carefully. There is a formulae relating source
resistance, proof voltage/actual voltage and capacitance.
Note early Plessey button tantalum (very reliable) incorporated liquid
conc nitric? dont blow them up!

--
ddwyer