Janitorial service is not a particularly dangerous business; the occasional fall or sprain usually covers it.
I did, however, run across an article about a lady in Madrid who died after a couple of hours of intense housecleaning, with ammonia but not much ventilation.
Ammonia used to be big in the industry. As a floor stripper, it's pretty effective; the rule of thumb 30 or 40 years ago was to add ammonia (one measured it by "glugs") to your commercial stripper if the wax looked particularly thick. You needed quite a lot of ammonia, and ventilation was of secondary concern (this being Phoenix, in the summer one wanted air conditioning much more than an open window).
Another variant on ammonia was to use it in the vicinity of, and occasionally in combination with, bleach - another good chemical. Mixed, they produce chlorine gas, which offed a good many folks on the Western front during WWI. (In passing, we figure that bleach and ammonia are both pretty noxious, and dangerous, so we use neither; if we use neither, it's pretty hard to goof and combine them on the job. But then, we're more than a bit concerned with safety.)
I tell myself those days are long gone; today, everybody is well informed and safety conscious.
Quoted a small construction firm this morning. Got a look at the current janitor's equipment, and chemicals, right there in the closet. Miscellaneous consumer level chemicals; no safety data sheets in sight (which makes the client, not the janitorial service, liable and open to OSHA fines). No sanitizer or disinfectant in sight, either. There was a can of scouring powder (ever inhale any of that?). Unfiltered vacuum (dumpable cloth bag only; no paper bag, much less any kind of filter, let alone a HEPA filter). String mop, and feather duster (filthy, in passing). Clearly, no safety gloves.
No bleach, or ammonia, but otherwise not much advanced from the 60's. Add together the violations, inappropriate chemicals, and lack of any concern for dust control, indoor air quality or client health, and you might almost wish for the ammonia.