In the late 1950s, 3M produced the first asthma inhaler, but the company did not enter the pharmaceutical industry until the mid-1960s with the acquisition of Riker Laboratories, moving it from California to Minnesota. 3M retained the Riker Laboratories name for the subsidiary until at least 1985. In the mid-1990s, 3M Pharmaceuticals, as the division came to be called, produced the first CFC-free asthma inhaler in response to adoption of the Montreal Protocol by the United States. In the 1980s and 1990s, the company spent fifteen years developing a topical cream delivery technology which led in 1997 to health authority approval and marketing of a symptomatic treatment for genital warts, Aldara. 3M divested its pharmaceutical unit through three deals in 2006, netting more than . At the time, 3M Pharmaceuticals comprised about 20% of 3M's health care business and employed just over a thousand people.