Can someone induce cancer in another person Is it possible to poison someone's food on a daily basis in order to give them cancer?

The thing here is that i'm worried someone at my workplace might be poisoning other people's water (each employee has his own packs of water bottles at their desks, also, this person seems to have some mental issues). 
It is possible to put chemicals in a bottle with no water leaking via a syringe. So my fear is that this bad person (this person IS bad., believe me) may have poisoned, in a daily basis for 3 or 4 weeks, our water. 

So the question is, could this person poison the bottles to make others get cancer? Or another highly dangerous disease?
[&hellip;] So the question is, could this person poison the bottles to make others get cancer? Or another highly dangerous disease?


Yes, in principle. 

Information on known cancerogenic compounds can be found in CMR (Canceogenic, Mutagenic and toxic to Reproduction) lists published by national organizations responsible for workplace safety. 

In Germany, this would be the IFA (Institut für Arbeitsschutz der Deutschen Gesetzlichen Unfallversicherung).

List with old nomenclature

List with new nomenclature

I have added these lists just for the sake of completeness!

If you suspect any of the activities that you described, contact the local authorities.