The demand for helmets made from declined with the advent of the industrial era
The demand for harnesses made from declined with the advent of the industrial era
The demand for stirrups made from declined with the advent of the industrial era
The demand for riding crops made from declined with the advent of the industrial era
The demand for halters made from leather later declined with the advent of the industrial era
The demand for saddles made from leather later declined with the advent of the industrial era
The demand for feed bags made from leather later declined with the advent of the industrial era
Football and aviation (pilot) helmets were constructed of leather.
NFL players were first required to wear helmets in 1943. At the time, they were made of leather. They then went to being made of plastic and now are made of polycarbonate.
some are made of leather, cheaper helmets are made of composite materials.
Leather, after 1916; steel.
The old helmets where made of cow skin leather
A Fireman's helmet is made from metals such as brass, aluminum and nickel. You can get more information about this at the Wikipedia. Once on the website, type "Firefighter's helmet" into the search field at the top of the page and press enter to bring up the information.