Removal of existing services
There may be structures or services that need to be removed from the site, such as an old septic tank or sludge pit, or old oil or petrol tanks. Sometimes areas of ground (both surface and substrata soil) become contaminated by leeching from tanks or chemical spills from neighbouring properties. Land may have been contaminated by lead which can be left behind from industry or old service stations.
EPA guidelines give information about the procedure for removal of contaminants. A site assessment is necessary when contamination is known or likely to be present. This involves checking the site's history and taking soil samples to identify the contaminants and their concentrations.
A risk assessment is necessary when a site assessment indicates the presence of contaminants that may be a risk to the health of workers on the site. If the risk cannot be completely removed, it should be reduced as much as possible.