I am not a legal expert by any means but I know most landlord insurance don't cover the tenant's property. It is upon the tenant to acquire renter's insurance or in the case of this tenant, a business insurance that protects his goods when its damaged.
Check the original lease clause. If the lease stated for the tenant to acquire renters insurance and the landlord is not responsible for any damages, then you are in the clear.
However, remember I am not a legal expert and only speaking from experience. I strongly encourage you to speak to an attorney about this so you can be prepared for anything this tenant throws at you.
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