Southwell Laboratory, Inc. (SL) is the oldest commercial laboratory in Oklahoma. SL was established in 1918 by Claude Ray Southwell, who was very active in the agricultural area of chemistry. C. R. Southwell was joined by his son, Joseph Ray Southwell, Sr. after serving in the air corps in World War II and the company continued to grow. With the retirement of C. R., Joe saw the need for expansion and in the early seventies invested in the modernization of the lab with extension of service to the environmental needs of the community and industry. In 1980 his daughter, Susie Southwell, joined him in his efforts to continue service to industry and community. In 1990, Southwell Laboratory achieved women owned small business status.