For the purposes of this article, the following terms shall have the meanings respectively ascribed to them by this section:
(1) OCCUPATIONAL EXPOSURE TO RADIATION. Gradual exposure to radiation over a period of time from the use of or direct contact with radium, radioactive substances, roentgen rays (X rays), or ionizing radiation, arising out of and in the course of the employment and resulting from the nature of the employment in which the employee is engaged, without regard to whether or not said exposure is inherent in the employment or can be eliminated or reduced by due care on the part of the employer. The term "occupational exposure to radiation" shall not include accidents involving sudden and violent injuries within the meaning of subdivision (9) of Section 25-5-1, such accidents being covered by such section.
(2) NATURE OF EMPLOYMENT. Such term shall mean that, as to the industry in which the employee is engaged, there is attached a particular hazard of such exposure that distinguishes it from the usual run of occupations and is in excess of the hazards of such exposure attending employment in general.