40 ILCS 5/6-112

"Disability": A condition of physical or mental incapacity to perform any assigned duty or duties in the fire service.

"Injury": Damage suffered by or hurt done to a fireman.

"Occupational Disease": A sickness, disease or illness of the heart, lungs, or respiratory tract of a fireman, arising solely out of his employment as a fireman, due to exposures to heat and extreme cold, inhalation of heavy smoke, fumes or poisonous, toxic or chemical gases while in the performance of active duty in the fire department. "Occupational Disease" also includes cancer.