Article Safety

Contamination During a Ground Investigation

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Tags: feautured

The Safety Working Group aims to provide guidance to inform practice and aims to produce regular updates throughout the year.  It was noticed by the group that a number of guidance documents on the AGS website are over 6 years old and may have been overlooked. The group has decided to put a focus on reviewing these older documents and either bring them up to date in line with current guidance or re-write them and withdraw as necessary.

The latest document to receive an overhaul was the outdated AGS guidance on safe intrusive investigation of contaminated land published in 2010. The Safety Working Group has replaced this with two complimenting documents published in September 2020. The documents have been written to aid with intrusive instigation on contaminated sites.

The main document ’Guidance on Dealing with Contamination During a Ground Investigation’ covers the importance of  a desk study, risk assessment, what equipment and PPE may be required, what should be considered in the event of an emergency and general safe working guidelines.

The secondary document ‘Comment on the Approach for Classifying Sites into Green, Yellow or Red provides guidance on the British Drilling Association’s (BDA) approach for classifying sites in to green, yellow or red sites.

The BDA is the UK’s trade association for the ground drilling industry. In 1992 they produced a ‘Guidance for Safe Intrusive Activities on Contaminated or Potentially Contaminated Land’ which introduced a site classification system (Green, yellow and red). This guide was revised in 2008 and has been adopted by the Site Investigation Steering Group to form an integral part of the national adopted specifications. The comment provided by the AGS includes notes on the application of these categories and indicates the type of controls, PPE and safety equipment required. It’s important to understand you cannot classify a site without first undertaking a desk study.

The AGS ‘Guidance on Dealing with Contamination During a Ground Investigation’ highlights a number of safety aspects that should be considered when working with contaminants including;

  • Preparation of a risk assessment covering exposure to potential hazards outside of the standard investigation tasks including; chemical, biological and physical hazards.
  • Consideration of additional or disposable PPE, including the potential need for decontamination facilities or increased welfare availability.
  • Training and advice for staff involved in the work so they are aware of the potential hazards.
  • Keep vaccinations up to date against tetanus. Other vaccinations may be necessary dependent on the nature of the site being visited such as landfills.
  • The need for health surveillance if a disease or adverse effect may be related to exposure that is likely to occur during the works.
  • Thorough cleaning of equipment that has been in contact with contaminated ground prior to demobilising.

It should be noted that the document is for guidance only  and the information contained is not exhaustive. The safety implications on any given site will vary depending on the extent of any known or encountered contamination. Additional references to further guidance are provided at the end of the document. Both documents are available to download free from our website – Guidance on dealing with contamination during a ground investigation can be downloaded here and Comment on the approach for classifying sites into green, yellow or red can be downloaded here.

If any readers of AGS Magazine have any comments or thoughts for the Safety Working Group, please do send comments across to for consideration.