Persons engaged in loading or unloading explosives shall not wear boots or shoes with iron nails, or shod or strengthened with iron, unless such boots or shoes are covered with leather, felt, or some other such material. City Code, 1927, art. 15, §80(1st sen.) 1950, art. 11, §82(1st sen.) 1966, art. 10, §81(1st sen.) 1976/83, art. 10, §81(1st sen.) Ord. 13-336