Upjohn acquired The Carwin Chemical Company in 1962. The Carwin Chemical Company started in North Haven in 1946 manufacturing chemicals for perfumes. Carwin Chemical started manufacturing organic intermediates (chemical compounds used as raw materials in industries) for domestic dyestuff and pigment manufacturers. When Upjohn purchased Carwin Chemical in 1962, they continued the manufacturing processes previously performed by Carwin. This included the manufacture of dichlorobenzidine(DCB).

Until its closure in 1993, Upjohn's North Haven Fine Chemical (NHFC) produced raw materials, organic chemical intermediates, and technical grade chemicals. Upjohn's products included: dichlorobenzidine, dihydrochloride, o-dianisidinedihydrochloride, 4-sulfophthalic acid, benzophenone, 2,2-diethoxyacetophenone. Upjohn also produced chemical compounds for instant-photography film, protecting fruits from decay, and intermediates for prescription pharmaceuticals. Click here for a list of data sheets send out by Upjohn to North Haven customers.

In 1989 the US EPA ordered The Upjohn Company to determine the pollution at the site and clean it up. This work has been completed and the site is now a nature preserve.