Re: How?
We'd have to see the proper report to know. A daily 45% injury rate sounds like a lie - or such a ridiculous misrepresentation of the figures that it's basically a deliberate distortion of the truth. How would you get anything done.
However if you're spending 8 hours a day packing boxes, unpacking other ones (probably with a sharp blade) and moving stuff about - you've got a good chance of getting cuts on your hands or dropping stuff on your feet. Plus fingers trapped between boxes or by the wheeled carts you use to move stuff around. And that's just the picking staff - I've worked for a courier company and if you're spending hours in the warehouse then your hands are in an unfriendly environment. That's before you talk about loading and unloading lots of trucks, forklifts, pallet trucks and the like. And something I didn't have to deal with was warehouses where stuff is stacked on 15' high shelves. Which people shouldn't be climbing on - but it happens if things aren't properly designed. And people will cut corners with safety rules to get stuff done quickly even if they're not being pressurised by management to work faster - and it gets even worse when they are (like at Amazon).
Of course this depends on how automated stuff is, because where I worked was a tiny firm with no money and one very small warehouse, plus 3 or 4 vans. Amazon should be a lot better - but they've got so many different products and different ways of stuff reaching their warehouses that I suspect it's all more manual than it should be.
You have to continually tell people off for breaches of H&S, even just basic stuff like bending your knees to lift stuff not your back - you can injure yourself even with quite lightweight stuff that way. Again, if things are well designed there shouldn't be anything at floor height, so you shouldn't need to bend at all.
There's all sorts of scope for injuries from the trivial (scratches and minor bruises) to the fatal. Plus if the warehouse isn't well designed and people are having to lift boxes you've got all the back injuries and muscle strains. Or stuff landing on people. But I'd have thought a certain amount of minor skin injuries are unavoidable, and your hands toughen up pretty quickly. Wearing gloves solves most of it, but makes you a bit clumsier for some jobs. I've never liked gloves and only worn them for the heaviest of jobs. I'd hope H&S has improved since my experience in 1992 though.