Construction workers are expected to wear protective footwear whilst on site and doing heavy work. The bones in the foot are quite delicate and easily damaged and any muscle or tendon damage can prevent normal movement for several months. Steel toecaps (or equivalent) protect against dropped objects. Midsole protection (usually a steel plate) protects against puncture or penetration if you tread on a nail. If you need to enter or work on a construction site, your employer will provide a basic standard of safety footwear.