sentences:  The club stadium, Herøya Stadion, has a capacity in surplus of 2000.Originally an island that was used for agriculture, in 1928 Norsk Hydro decided to locate a new artificial fertilizer factory there, Hydro Porsgrunn, and in just 16 months both this factory and a shipping port for Norwegian saltpeter (calcium nitrate) were built.In the process, the narrow sound between the island and the mainland was mostly filled up, thus transforming the island to a peninsula.