It is very important to report suspected occupational diseases in Iceland to the Administration of Occupational Safety and Health, so they can be diagnosed, investigated in details and improvements made. This article describes the illness of clam workers at Thornórshöfn, a small village in the northern part of Iceland. It lead to a detailed investigation and the diagnosis of clamworkers hypersensitivity pneumonitis. Many specialists participated in the study that lead to improvement in the factory that has benefitted the workers.