The Contamination Hazard Assessment Tool (CHAT) is designed to aid in prioritising the investigation of contamination across the Defence Estate, particularly where no prior investigations and formal risk assessment has been carried out. The CHAT was developed to identify the key source‐pathway‐receptor characteristics at Defence facilities across the Defence estate. This will assist in determining the risks associated with the contamination.
A CHAT Questionnaire in an excel spreadsheet format is used to capture information including source‐pathway receptor attributes to determine the risks.
A CHAT Guidance Document provides the technical background the questionnaire to assist in completing a CHAT for a site.
The NCRP and Regional Environment Officers should use CHAT prior to creating a new CSR entry. This will ensure a consistent and robust assessment procedure in ranking new sites. The Questionnaire was developed to limit bias and to provide for the identification of data uncertainty by allowing only for a ‘yes/no/not known’ answer to reduce interpretation (and bias) by the respondent. The decision rule developed as part of the Questionnaire then assigns a Hazard Category based on the answers to each question.Relevant background and explanation on the use of the questionnaire is set out in the Guidance Document.