The decision is a result of the major changes Hydro has gone through over the last 10-15 years, going from a conglomerate operating in several business sectors to a pure aluminium company with its own significant electric power production.

Fertilizer production, which played such an important role in Hydro's history, went over to Yara when it was spun off from Hydro in 2004. The petrochemical business was sold to Ineos in 2008, while magnesium production was wound down in 2001 in the face of severe competition from China.

"For many years Hydro has made a major effort to develop the industrial park and encourage the creation of new businesses in Grenland. As a result, there are now around 80 companies here at Herøya with a total of 2500 employees," says executive vice president Eivind Kallevik in Hydro.

He notes that there are only about 75 Hydro employees left in Herøya. Most of them work on operating and developing the industrial park itself, and in the research center.

"The decision to sell is therefore a natural consequence of developments in Hydro and at Herøya Industrial Park in recent years," he says.

Kallevik explains that the sales process will be standard and open, where potential local, Norwegian and international buyers will be invited to make offers. The overall goal is to find a professional owner with the resources and expertise to run and further develop the industry park.

It is not known how long the sales process will take, but he estimates that a new owner will be in place by the end of the year.

Hydro is planning to sell the assets made up of Herøya Industripark AS and Herøya Nett AS, including the properties, buildings, infrastructure, electricity grid and process water supplies. After the sale, about 50 employees will be transferred to the new owner.

Industrial activity began in Herøya early in the summer of 1929 with the establishment of the Eidanger saltpeter factory. Fertilizer production was based on ammonia from Rjukan. The facilities were gradually expanded, first through the increased production of fertilizer and its by-products, and later with the addition of PVC and magnesium. At the peak in the 1960s, Hydro employed around 6500 people in Herøya.