Terms used in this chapter mean:
(1) "Compensation," the payments and benefits provided for in the South Dakota workers' compensation law, subject to the conditions and limitations contained in this chapter;
(2) "Department," the Department of Labor and Regulation of the State of South Dakota;
(3) "Disablement," the event of an employee's becoming actually and totally incapacitated, because of an occupational disease as defined in this chapter, from performing work in the last occupation in which injuriously exposed to the hazards of such disease. The terms, disability, disabled, total disability, totally disabled, or total disablement are synonymous with disablement;
(4) "Injurious exposure" and "harmful quantities,' ' that concentration of toxic material which would, independently of any other cause whatsoever (including the previous physical condition of the claimant) produce or cause the disease for which claim is made;
(5) "Nondisabling silicosis," silicosis demonstrable by X ray examinations of the lungs, which reveal unquestionably the characteristic mottling of silicosis in the lung fields, occurring in an employee after injurious exposure to silicon dioxide for the period provided in § 62-8-14, but not sufficient to disable the employee from performing usual work;
(6) "Occupational disease," a disease peculiar to the occupation in which the employee was engaged and due to causes in excess of the ordinary hazards of employment and includes any disease due or attributable to exposure to or contact with any radioactive material by an employee in the course of employment;
(7) "Silicosis," the characteristic fibrotic condition of the lungs caused by the inhalation of silicon dioxide (SiO2) dust.