TV Tropes diz:
It's mentioned that the American facility has only failed to complete its ritual once before, in 1998, due to a screw-up by the Chem Department. Was that date chosen at random, or was a movie released that year that Joss Whedon thought was exceptionally-lame, even for schlock horror?
A melhor explicação parece ser The Faculty , já que não teve fatalidades, exceto [ver spoiler abaixo], e faz sentido com a parte do departamento de química:
Scoping a list of 1998 horror films, the only one that sticks out is The Faculty. There isn't a single fatality within the main cast of students (save for the "Virgin" who is ultimately revealed as the monster). And to make matters worse the monster's undoing turns out to be the stoner's custom mix. Damn chem department indeed...