Why were the zombies 'bathing' in the formaldehyde?

When the convicts return to the prison camp as zombies, there are several scenes where they're crowding into the formaldehyde-production area, splashing it over their faces, rubbing it into their clothes, etc. What's up with that? I know they were all hooked on sniffing the stuff before they died, so were they REALLY jonesing for a hit of it or was it to keep them from decomposing any further than they already were?

Speaking of decomposition, those zombies already looked pretty raggedy for a bunch of guys who were barely buried before they popped back out of the ground again. How long had they been buried, a few hours at most? Their clothes and general pallor looked like they'd been underground for weeks. Must be highly acidic soil.

...and why the hell was a prison manufacturing formaldehyde in the first place? I was under the impression that prisoners make license plates.

These are just a few of the things that bother me about this cheap ass slab o' zombie cheese. Anyone have any theories?

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