General view of the caustic soda evaporators at the Dow Chemical Company plant located in Freeport, Texas. Also known as sodium hydroxide, caustic soda was commonly used to produce ethyl cellulose per the process developed by Edgar Britton in Dow's Organic Laboratory. Dow also sold caustic soda for use in the manufacture of soap, lye, rayon, and wood pulp for paper, as well as the refining of petroleum, mineral and vegetable oils, and fats.