Litter clumps were first developed by using calcium bentonite clay. This was manufactured in the UK in the 1950s by the Fuller's Earth Union (FEU), which later became a part of Laporte Industries Ltd. Subsequently in America, clumping bentonite was developed in 1984 by biochemist Thomas Nelson. Most are made from granulated bentonite clay, which clumps together when wet and forms a solid mass separate from the other litter in the box. This solid clumped material can be scooped out and disposed of without changing the entire contents of the litter box.