The Occupational Safety and Health Administration is the primary federal agency charged with the enforcement of workplace safety and health legislation. Construction sites are potentially very hazardous workplaces, and many of OSHA's most publicised requirements are applied to the construction industry. One of the most visible is the enforcement of hard hats on the job site, from the newest worker to the executive on-site.
OSHA Standard 1926.1000 requires the use of head protection, such as hard hats, at any job location where there is a "possible danger of head injury from impact, or from falling or flying objects, or from electrical shock and burns".
According to a 1977 letter from Eula Bingham, OSHA Assistant Secretary, employers and OSHA observers should evaluate "with good judgment" the head injury hazards of specific situations. This takes into account that there are countless situations and jobs that might not necessitate wearing a hard hat, even while on a job site.
Employees who object to wearing hard hats because of personal convictions, including the religious practices of the Sikhs and Amish, may be exempted from the OSHA requirement. This requires employers to enact additional training on workplace safety and the avoidance of head injuries.
Any hard hat worn in the workplace must meet standards set by the American National Standard Institute: ANSI Z89.1-2003, "American National Standard for Industrial Head Protection," ANSI Z89.1-1997, "American National Standard for Industrial Head Protection," or ANSI Z89.1-1986, "American National Standard for Personnel Protection -- Protective Headwear for Industrial Workers--Requirements." Alternate head protection that the employer proves are equally effective as any of the above standards may also be used.
Because hard hats must be inspected for dents, cracks and other imperfections before use, personalisation of helmets is prohibited by OSHA, to a degree. Any personalisation must be within the manufacturer's guidelines to prevent the elimination of electrical resistance, and any stickers or markings must allow the helmet underneath to be inspected for dents and cracks. Paints must also be selected according to manufacturer's standards, as some solvents and thinners can make a hard hat more prone to damage.