Early american football helmets were made of leather and had some padding on the inside, but the padding was insufficient and provided little protection. In addition, they lacked face masks. They also absorbed a lot of heat, making them uncomfortable to wear.
In 1938 The Riddell Company based in Chicago, Illinois started manufacturing plastic helmets because it felt that plastic football helmets would be safer than those made of leather. Plastic was found to be more effective because it held its shape when full collision contact occurred on a play. These football helmets were also much more comfortable and had more padding to cushion the head in an impact. Included with the plastic helmet came plastic face masks, which allowed the football helmet to protect the entire head. By the mid-1940s, football helmets were required in the NFL.