(a) Findings and declaration of fact. The following occupations involved in the manufacture of clay construction products and of silica refractory products are particularly hazardous for the employment of minors between 16 and 18 years of age, and detrimental to their health and well-being.

(1) All work in or about establishments in which clay construction products are manufactured, except (i) work in storage and shipping: (ii) work in offices, laboratories, and storerooms; and (iii) work in the drying departments of plants manufacturing sewer pipe.

(2) All work in or about establishments in which silica brick or other silica refractories are manufactured, except work in offices.

(3) Nothing in this section shall be construed as permitting employment of minors in any occupation prohibited by any other hazardous occupations order issued by the Secretary of Labor.

(b) Definitions. (1) The term clay construction products shall mean the following clay products: Brick, hollow structural tile, sewer pipe and kindred products, refractories, and other clay products such as architectural terra cotta, glazed structural tile, roofing tile, stove lining, chimney pipes and tops, wall coping, and drain tile. The term shall not include the following non-structural-bearing clay products: Ceramic floor and wall tile, mosaic tile, glazed and enameled tile, faience, and similar tile, nor shall the term include non-clay construction products such as sand-lime brick, glass brick, or non-clay refractories.

(2) The term silica brick or other silica refractories shall mean refractory products produced from raw materials containing free silica as their main constituent.