Industrial sites are first decommissioned (ie. removal of structures) then reclaimed to original conditions (contamination is assessed to determine whether the site needs to be treated or remediated).
Oil refinery in Ghent harbour, Belgium. Civil engineers are involved in the cleanup of 600,000 m3 of contaminated material.
Oil Strike: January 2000 issue of the New Civil Engineer International
The Brent Spar oil storage buoy was originally to be sunk but there were objections to this idea. After decommissioning, 70 % of the structure was reused, 20% of material recycled, ballast water treated and oil and sludge recovered.
Decommissioning of Brent Spar, Stavanger, Norway: 19/10/2000 issue of the New Civil Engineer