I wonder if the 911 call rate is any higher than the general non working population as a whole, sitting in private residences on couches.
189 calls / 5 years = 37.8 calls per year
37.8 calls / 46 warehouses = 0.82 calls per year, per warehouse
Now assume for a moment, this is probably a low estimate, that a single warehouse has a peak day shift population of 75 persons...
One of the things I have learned first hand, doing VoIP E911 and site address registration for E911 purposes, if you have a sufficiently large number of people (or in my case, live / on-net individual VoIP service circuits), there will be a certain statistically "normal" volume of 911 calls no matter what those people are doing.
Whether they're in a office of a company that rents two floors of a 350,000 square foot office tower in a downtown of a major city, sitting on their couches in a single family home in a suburb playing videos games on their xbox, attending a music festival, literally any imaginable human activity.
I am not trying to say that the Amazon warehouse jobs are not borderline abusive and a staff turnover meat-grinder, they probably are. Have read numerous reports from journalists that have gone "undercover" with the temp/staffing agencies Amazon uses to hire workers for their warehouses. It doesn't paint a pretty picture.