The industrial gases specialist Messer is currently investing 35 million euros in the construction of a production plant for the atmospheric gases oxygen, nitrogen and argon on the Deutsche Edelstahlwerke site in Siegen. From October on, air will be separated into its components in the 55-metre rectangular tower, the so-called coldbox, in order to recover the gases. In a complicated lifting procedure, the heart of the plant, an aluminium column, 45 tonnes in weight and 53 metres long, is now being fitted. The separator column, suspended on steel belts, is hoisted precisely into the coldbox by three industrial cranes working simultaneously.

Messer's air separation unit is being constructed on an area of 10,000 square metres and, in the autumn, will supply Deutsche Edelstahlwerke itself, among others, with industrial gases. In the air separation unit, dried air with CO₂ removed is liquefied and then separated into its components. In this way, oxygen, nitrogen and argon are recovered in gaseous and liquid form. The aluminium separator column is the heart of the air separation unit. In this column, liquefied air is split into its main components by a thermal separation process, rectification. This is a purely physical process, in which no chemical reactions take place.

With the construction of the air separation unit in Siegen, five new jobs have been created at the Deutsche Edelstahlwerke site. In mid-2008, Messer was able to create 20 new positions, mostly in the commercial area, in the newly built Sales and Logistics Centre for Industrial Gases in Siegen-Kaan Marienborn. About 35 skilled workers from the region are currently employed on the construction site, working on more than 5,500 cubic metres of concrete, 1,200 square metres of masonry and about 570 tonnes of steel. The permit for the operation of the production unit for industrial gases in accordance with Germany's Federal Immission Control Act (BImSchG) was officially issued long ago. This law serves, among other things, for protection against harmful effects on the environment, such as noise.