When my father was a young fibreglass worker (many many years ago) he said they were fibreglassing the inside of a tank, and would take bets on who would last longest before passing out!!!

In some lines of work, having a cellphone of some sort on your person can be important in case you are accosted. Look at the flack that DOC went through recently!
However if it is outside your normal working hours then your work cellphone should be off. This is important for your own wellbeing.
We talk and talk about the work/life balance. How can you have that if you are looking at your work phone at home?

Is this like some government departments banning office houseplants due to "H&S"?

https://www.stuff.co.nz/national/101441108/office-plants-labelled-a-safety-hazard-by-some-government-departments