The owner of any dwelling, dwelling unit or rooming unit, industrial or commercial structure which has been declared unfit for human occupancy or which is otherwise vacant for a period of 60 days or more shall make same safe and secure so that it is not hazardous to the health, safety and welfare of the public and does not constitute a public nuisance. Any vacant dwelling open at doors or windows, if unguarded, shall be deemed to be a hazard to the health, safety and welfare of the public and a public nuisance within the meaning of this chapter.
(`89 Code, § 27.330)