Employees exposed to the hazard of being struck by flying or falling objects must wear protective helmets (hard hats) that comply with ANSI Z89.1 standards. Hard hats must be maintained in good condition and replaced if damaged, dented, cracked, or exposed to impact. The suspension system inside the hat must not be altered or removed, as it provides the critical impact-absorbing function. Hard hats must be worn correctly with the bill forward or backward depending on hazard location, and must not be removed during work in hazardous areas. Different types of hard hats provide protection against different hazards: Class A protects against impacts from light objects and minor electrical shock; Class B provides protection from electrical shock up to 20,000 volts; Class C offers no electrical protection but is lighter for comfort. Hard hats must be selected based on the specific hazards present on the job site. Hair nets or hoods may be worn under hard hats in appropriate circumstances. All workers in construction must be trained on when and where hard hats are required, proper wearing procedures, and inspection requirements. Hard hats must be replaced if the suspension system is damaged or deteriorated, typically every 3-5 years or per manufacturer recommendations. Employers must provide hard hats at no cost to employees and enforce their use through supervision and discipline.