Hello and welcome to JustAnswer. Please note: This is general information for educational purposes only and is not legal advice. No specific course of action is proposed herein, and no attorney-client relationship or privilege is formed by speaking to an expert on this site. By continuing, you confirm that you understand and agree to these terms.
I am sorry to hear about this situation. In the end, this depends on what started the fire. Period.
If it was the tenant's fault that the fire started, then the landlord is not responsible for the damage.
If it was the landlord's fault that the fire started, then the landlord would be responsible for the damage.
This is not an "asbestos" case as much as it is a case of negligence.
The problem is that the cause is undetermined. If the FD had a sure cause stated, then the parties can use that cause as evidence in suing each other (or negotiating). FD's decision abut the cause can be challenged, but it does serve as strong evidence so is mostly followed by the parties and the court. But since there is no cause mentioned, the parties may have to "duke it out" in Court, and then the Court (Judge or jury) would decide who was responsible for the fire based on the evidence that is available, which is the FD report, witnesses, and statements.
Please note: If I tell you simply what you wish to hear, this would be unfair to you. I need to be honest with you and sometimes this means providing information that is not optimal. Negative ratings are reserved for experts who are rude or for erroneous information. Please rate me on the quality of my information; do not punish me for my honesty.
I hope this helps and clarifies. Please use the SEND or REPLY button to keep chatting, or please RATE when finished. You may always ask follow ups at no charge after rating. Kindly rate my answer as one of TOP THREE FACES/STARS and then SUBMIT, as this is how experts get credit for our time. Rating my answer the bottom two faces/stars (or failing to submit the rating) does not give me credit and reflects poorly on me, even if my answer is correct. I work very hard to formulate an informative and honest answer for you; please reciprocate my good faith with a positive rating.