Toilets that are just Holes in the ground can go burn
From Spike Milligan's autobiography:
Sanitary Orderly Liddel was learning the trade of maintenance on the out door hole-in-the-ground latrines. The lime powder that is normally used to 'sprinkle' the pit, had not arrived. He, being of an inventive turn of mind, mixed petrol and diesel and used that. Dawn! Enter an R.S.M. pleasure bent! He squats on pole. Lights pipe, drops match. BOOOOOOOOM! There emerges smoke-blackened figure, trousers down, smouldering shirt-tail, singed eyebrows, second degree burns on bum
I mean that's fair for armies on campaign. Used to be they pretty much just shat outside their tents, which standards of hygiene of course did nothing to lessen the routinely hideous attrition from diseases.
For peacetime civil engineering, not so much.