Since its discovery to Europeans by John Smith in 1614, Boston Harbor has been an important port in American history. It was the site of the Boston Tea Party as well as almost continuous backfilling of the harbor until the 19th century. By 1660 almost all imports came to the greater Boston area and the New England coast through the waters of Boston Harbor. A rapid influx of people transformed Boston into a booming city. The health of the harbor quickly decreased as the population of Boston increased. As early as the late 19th century Boston citizens were advised not to swim in any portion of the Harbor. In the 19th century two of the first steam sewage stations were built (one in East Boston and one later on Deer Island). With these mandates the harbor was seeing small improvements, but raw sewage was still continuously pumped into the harbor. In 1919 the Metropolitan District Commission was created to oversee and regulate the quality of harbor water. However, not much improvement was seen and general public awareness of the poor quality of water was very low. In 1972 the Clean Water Act was passed in order to help promote increased national water quality.