C.R.S. § 18-4-102: First degree arson.

(1) A person who knowingly sets fire to, burns, causes to be burned, or by the use of any explosive damages or destroys, or causes to be damaged or destroyed, any building or occupied structure of another without his consent commits first degree arson.

(2) First degree arson is a class 3 felony if the arson is of an occupied structure, and it is a class 4 felony if the arson is of a building.

(3) A defendant convicted of committing first degree arson by the use of any explosive shall be sentenced by the court in accordance with the provisions of section 18-1.3-406.