The first rental property that I purchased during my second attempt at being a landlord had a fire last week. The tenants had just moved in 5 days previously and had a fire in the fireplace. They went to sleep at 1:30 and the smoke alarms woke their kids at 4am. Luckily the previous tenants had moved and I had replaced the smoke alarms (the previous tenants had disabled them). The smoke detectors saved the lives of these tenants.
Unfortunately for the tenants they did not have renters insurance. However, I did have landlords insurance policy which covers loss of rental income. My policy also has a clause which requires the insurance company to cover any upgrades required to meet building codes. This is a lifesaver since my locality requires that any time a building permit is issued upgrades to older homes are required.