Hot answers tagged zombie-invasion
Is it Fear Itself: Season 1, Episode 6 ( New Year's Day ), from IMDb's synopsis all plot-line is matching. Here is full Wikipedia summary of the episode. Even the ending of the episode is matching with your provided details.
Seems it's Night Life from 1989. All the details are there (teenagers, prom, chemical truck, wood chipper, overpumping someone to death). Beware - graphic images inside: http://www.the-losthighway.com/2013/02/17/night-life-1989/
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