The variety of plastic objects at risk is dizzying: early radios, avant-garde sculptures, celluloid animation sills from Disney films, the first artificial heart.
By the middle of the century, American entrepreneurs discovered that dipping nitrocellulose in wax turned it into a hard, enduring substance, and patented it as celluloid.
So in the late 1800s and early 1900s, celluloid accessories were everywhere -- buttons, jewelry, eyeglass frames, toys, and little hair combs that ladies would wear.
A 38mm ball made from celluloid quickly became the standard and was used all the way up until very recently when in 2000 the ball size increased to 40mm.