I have since revisited this location. See newer pics here.
Lever Soap Plant of Saint Louis was built in 1953 and lasted nearly 50 years in operation, before closing in 2001 as a result of restructuring.
"Lever Brothers was a British manufacturer founded in 1885 by William Hesketh Lever (1851–1925) and his brother, James Darcy Lever (1854–1910). The brothers had invested in and promoted a new soap making process invented by chemist William Hough Watson, it was a huge success. Lever Brothers merged with Margarine Unie in 1930 to form Unilever." - wiki