I've heard of using shed snake skin powder as a deterrent.

Perhaps you could look up all the non-poisonous ways to control the rodent population, print it out, and hand a packet to the other tenant and landlord. Include information of course on just how dangerous Decon is and how it makes any animal that consumes it suffer. All the gory details of what it does internally.

(We were SOOOOO mad when we did the inspection on this house and it was almost perfectly clean, then when we moved in there was Decon EVERYWHERE. ARRRRG!!! )

(We mostly use snap traps, but we also use the humane traps.)