The Swiss chemical industry is a major economic sector with over 29,000 employees. It generates important added value. The roots of the industry are to be found in the Pratteln salt mine which opened in 1837. To this day, salt is being mined in the areas close to the banks of the Rhine river. The chemical industry gave rise to a particular infrastructure, including ports on the Rhine with their hubs for handling dangerous goods, dedicated industrial zones and its dock railway.