Sawdust is a by-product of cutting lumber

Lumber

Lumber or timber is wood in any of its stages from felling through readiness for use as structural material for construction, or wood pulp for paper production....

 with a saw

Saw

A saw is a tool that uses a hard blade or wire with an abrasive edge to cut through softer materials. The cutting edge of a saw is either a serrated blade or an abrasive...

, composed of fine particles of wood

Wood

Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

. It can present a hazard in manufacturing industries, especially in terms of its flammability.

Sawdust has a variety of practical uses, including serving as a mulch

Mulch

In agriculture and gardening, is a protective cover placed over the soil to retain moisture, reduce erosion, provide nutrients, and suppress weed growth and seed germination. Mulching in gardens and landscaping mimics the leaf cover that is found on forest floors....

, as an alternative to clay cat litter

Litter box

A litter box, sometimes called a sandbox, sand box, litter tray, litter pan, dirt box, catbox, or cat box, is an indoor feces and urine disposal box for cats that are permitted free roam of a home but who cannot or do not always go outside...

, as a fuel

Fuel

Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...

, or for the manufacture of particleboard. Until the advent of refrigeration, it was often used in icehouses

Icehouse (building)

Ice houses were buildings used to store ice throughout the year, prior to the invention of the refrigerator. Some were underground chambers, usually man-made, close to natural sources of winter ice such as freshwater lakes, but many were buildings with various types of insulation.During the...

 to keep ice frozen during the summer.