1. Every multiple dwelling, including its roof or roofs, and every part thereof and the lot upon which it is situated, shall be kept in good repair. The owner shall be responsible for compliance with the provisions of this section; but the tenant also shall be liable if a violation is caused by his own wilful act, assistance or negligence or that of any member of his family or household or his guest. Any such persons who shall wilfully violate or assist in violating any provision of this section shall also jointly and severally be subject to the civil penalties provided in section three hundred four.2. Whenever, the light, ventilation, or any matter or thing in or about a multiple dwelling or part thereof, or in or about the lot on which it is situated, is in the opinion of the department in a condition or in its effect dangerous to life or health, the department may order or cause any such light, ventilation, matter or thing to be repaired or improved or, as provided in section three hundred nine, take such other action as it may deem necessary to remove such danger to life or health.N.Y. Mult. Dwell. Law § 78