FOEN, Topics > Contaminated sites > Information for specialists > Remediation of contaminated sites > Preliminary investigation, 2021-02-10 ([Internet, 2024-05-22](https://www.bafu.admin.ch/bafu/en/home/topics/contaminated-sites/info-specialists/remediation-of-contaminated-sites/contaminated-site-management---step-2--preliminary-investigation.html))