§ Mr. Bestasked the Secretary of State for Employment what warnings are carried on containers of fluoride for addition to water supplies.
§ Mr. Peter Bottomley[pursuant to his reply, 26 February 1985, c. 129]: The majority of water authorities use hydrofluorosilicic acid solutions for fluoridation, though some limited use is made of sodium fluorosilicate.
Hydrofluorosilicic acid solutions — also known as fluorosilicic acid or fluorsilicic acid — are usually delivered in bulk by road tankers subject to the Dangerous Substances (Conveyance by Road Tankers and Tank Containers) Regulations 1981. The tanker would need to be placarded to warn of the corrosive properties of the solution, unless diluted to a safe level. The placarding would include the hazard warning sign for a corrosive substance together with other information for the emergency services in the event of a fire, spillage or other accident.
Sodium fluorosilicate, a powder, is usually delivered in bags. These have to be labelled in accordance with the Classification, Packaging and Labelling of Dangerous Substances Regulations, 1984, to show the toxic properties of the undiluted substance. The label would 183W carry a danger symbol and the risk phrase "toxic by inhalation, in contact with the skin and if swallowed"; it would also include prescribed safety advice.
These precautions are aimed at safety in conveyance and use of the substances named. They have no bearing on water supplies treated with these substances.