Buncefield Oil Depot Fire

My hon. Friend makes an excellent point. Rather by accident, we have discovered that PFOS seems to be widespread. The early indications suggest that its presence is not just related to Buncefield; it could be anywhere. I hope that the sampling process will be thorough and widespread and that we do not assume that the presence of PFOS is related only to firefighting. There is a concern about how widespread it may be and I shall be grateful for an update on any progress in that respect. Anxieties about PFOS have been heightened by the fact that 800,000 litres of stored firewater from Blackbird Lees sewage treatment near Radlett was accidentally released into the water supply. I understand that it was treated and there has been no evidence of PFOS as a consequence, but it is a major concern.