(i) "industrial accident" shall be defined as a case in which a worker is injured, contracts a disease or is killed due to causes attributable to buildings, facilities, raw materials, gases, vapors, dusts, etc., in or with which he is employed, or as a result of his work actions or attending to his duties;
(ii) "worker" shall be defined as in Article 9 of the Labor Standards Act (excluding a person who is employed at an undertaking or office at which only relatives who are living together are employed, and a housework employee.);
(iii) "employer" shall be defined as one who carries on an undertaking and employs a worker or workers;
(iii)-2 "chemical substance" shall be defined as an element or a compound;
(iv) "working environment measurement" shall be defined as measurement design, sampling and analysis (including analytical research) carried out on the atmospheric environment and other working environments in order to grasp the actual conditions of the working environment.