Published August 2022. This version replaces the previous version published September 2020 and ‘Guidance for safe intrusive investigation of contaminated land’ document, which was published in 2010.

In 1992 the British Drilling Association (BDA) first published “Guidance Notes for the Safe Drilling of Landfills and Contaminated Land” in response to a significant increase in requirements for drilling in these situations. These guidance notes were subsequently adopted by the Site Investigation Steering Group (SISG) into Part 4: Guidelines for the Safe Investigation by Drilling of Landfills and Contaminated Land. In 2008 the BDA reviewed their guidance to take account of many changes in ground investigation including changes in legislation, changes in working practices etc.

This article has been prepared to give help in applying the categorisation systems given in the guidance document produced by the BDA. It is vital that the full published guide is read to appreciate the impact of the potential hazards which may be present on contaminated land. The guide covers much more than the issues of categorisation