Contractors are often obliged to accept responsibility for the commercial risks arising out of the presence of contamination on site, including any unforeseen pre-existing contamination. Contractors should note that last month DEFRA issued further guidance. The guidance contains extensive provisions for dealing with contamination and it is clear that it will be costly and time consuming to comply with those provisions. Therefore, before agreeing to be responsible for contamination, contractors and sub-contractors should make sure that they are aware of the risks, have the benefit of robust warranties from the relevant consultants and have adequate insurance in place.