Section 150.05 - Arson in the fourth degree1. A person is guilty of arson in the fourth degree when he recklessly damages a building or motor vehicle by intentionally starting a fire or causing an explosion.2. In any prosecution under this section, it is an affirmative defense that no person other than the defendant had a possessory or proprietary interest in the building or motor vehicle. Arson in the fourth degree is a class E felony.