§ Mr. Etherington
To ask the Secretary of State for the Environment, Transport and the Regions if he will list the chemical compounds added to the public water supply in England and Wales, indicating which is used for(a) water treatment, (b) ingestion and (c) other purposes; and if he will give details of the most recent safety tests carried out by his Department on each such compound. 
§ Mr. Mullin
The Water Supply (Water Quality) Regulations 1989 provide for the approval of products, substances and processes used in the provision of public water supplies. The Secretary of State is advised on approvals issues by the Committee on Chemicals and Materials for Use in Public Water Supply. The Secretary of State's List of Approved Products, which includes all chemicals approved for use in public water supplies, is published annually by the Drinking Water Inspectorate. The list is installed on the Inspectorate's website www.dwi.detr.gov.uk
Approved chemicals are classified according to whether they are used for water treatment or other purposes. Where residues of the chemical are likely to be ingested, a condition of approval imposes a maximum dosing concentration as a public health protection measure.