Tenant garbage removal

[Sami Gren]

HI ALL. 

my tenant has pieces of broken furniture in the back stairway for a few month,

my question is first if all is it a fire hazard? (She is on the top floor so no other tenants need to pass)

2. If she puts it outside in garbage and the city doesn't pick up such stuff, am I required to pay for cremoval?, how should I go about it