The pharmaceutical industry developed in the late 19th century as a consequence of both scientific and commercial innovations, such as the development of diphtheria antitoxin and the commercialization of smallpox vaccine. Two tetanus outbreaks in 1901-from contaminated diphtheria antitoxin in St. Louis, Missouri, and contaminated smallpox vaccine in Camden, New Jersey-raised public concern about pharmaceutical safety. In St. Louis, errant manufacturing processes were found to be the source of the outbreak. In Camden, investigation identified contaminated vaccine from one manufacturer as the cause. These investigations, the first known pharmacoepidemiologic studies, were widely reported. They formed the basis for the 1902 Biologics Control Act, which focused on the safety of biologics produced and sold by the pharmaceutical industry and established a precedent of federal regulation of this industry. That power, welcomed by manufacturers to restore the public's trust in their products, was enhanced in the 1906 Food and Drug Act, which created the Food and Drug Administration.