The UK's very first hard hat was the bowler hat, designed in the late 1800s for gamekeepers patrolling their employers' estates on horseback, to protect them from being hit on the head by low branches, or from being hit over the head by poachers!
The first hard hat for industrial use was produced in 1919 by the San Francisco-based Bullard company. It was inspired by the "doughboy" helmet, used by soldiers in the First World War. Known as the "hard-boiled hat", it was made using steamed canvas, glue and black paint. Bullard soon incorporated a suspension device into its hat.
America's first designated hard hat area was set up at the San Francisco Golden Gate Bridge construction site in 1933. By 1938, aluminium had become the preferred material for hard hats, though it couldn't be used in electrical applications. In the 1940s, fibreglass superseded aluminium as the industry standard material and this was replaced in turn by thermoplastics in the 1950s and 1960s. Today, most hard hats are made from high-density polyethylene.