Ind. Code § 36-8-8-12.5

(1) Whether the fund member has a Class 1 impairment. A Class 1 impairment is a covered impairment that is the direct result of one (1) or more of the following: (A) A personal injury that occurs while the fund member is on duty. (B) A personal injury that occurs while the fund member is off duty and is responding to: (i) an offense or a reported offense, in the case of a police officer; or (ii) an emergency or reported emergency for which the fund member is trained, in the case of a firefighter. (C) An occupational disease (as defined in IC 22-3-7-10). A covered impairment that is included within this clause and subdivision (2) shall be considered a Class 1 impairment. (D) A health condition caused by an exposure risk disease that results in a presumption of disability or death incurred in the line of duty under IC 5-10-13. (2) Whether the fund member has a Class 2 impairment. A Class 2 impairment is a covered impairment that is: (A) a duty related disease. A duty related disease means a disease arising out of the fund member's employment. A disease shall be considered to arise out of the fund member's employment if it is apparent to the rational mind, upon consideration of all of the circumstances, that: (i) there is a connection between the conditions under which the fund member's duties are performed and the disease; (ii) the disease can be seen to have followed as a natural incident of the fund member's duties as a result of the exposure occasioned by the nature of the fund member's duties; and (iii) the disease can be traced to the fund member's employment as the proximate cause; or (B) a health condition caused by: (i) an exposure related heart or lung disease; (ii) an exposure related cancer; or (iii) exposure related Parkinson's disease; that results in a presumption of disability incurred in the line of duty under IC 5-10-15. (3) Whether the fund member has a Class 3 impairment. A Class 3 impairment is a covered impairment that is not a Class 1 impairment or a Class 2 impairment.