§ 150.05  Arson in the fourth degree.
    1.   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.