Sounds like the employer has created its own problems.

If an employee is doing an unpleasant, dead-end job with no prospect of advancement, they have to make a value judgment. If there's no prospect of advancement or any kind of wage growth (they're "low skill", so they'll be replaced if someone cheaper comes along), let alone security, then why stick around?

If the working conditions (e.g. heat and noise) are unpleasant, they could be improved. A ramp into other positions could be built to make the "job" an entry point to a "career" (e.g. Costco moves people between many different low skill jobs and then recruits from that pool for management).