§ Mr. George
asked the Secretary of State for Employment if he will make a statement on the accident caused by poisonous arsenic gas from ISC Alloys Ltd., Bloxwich.721W
§ Mr. Harold Walker
I have been informed by the Chairman of the Health and Safety Commission that no accident was caused by gas at the factory of ISC Alloys Ltd. at Bloxwich. The manufacturing process carried on at this factory leaves a residue of zinc dross. A consignment of this dross was sent to another factory at Market Drayton for recovery treatment. Employees at the Market Drayton factory were overcome by arsine gas which was evolved from the zinc dross.
Arsine gas can be liberated when acids react with metals containing arsenic and also by the action of water on hot dross containing arsenic and aluminium. Zinc ores frequently contain traces of arsenic, and so the possibility of the evolution of arsine from zinc dross always exists. Rainwater, especially in industrial areas, is frequently acidic because acid gases such as sulphur dioxide which may be present in the atmosphere are dissolved in it. The reaction between acidic rain water and zinc dross could produce arsine gas.
Exhaustive tests were carried out at ISC Alloys Ltd., Bloxwich, by staff of the Health and Safety Executive using a mobile laboratory. These tests revealed that contaminated materials were on the premises. Following advice from Her Majesty's Factory Inspectorate, the company has taken certain precautionary measures. A tip of zinc dross has been fenced off at a safe distance, the residues of zinc dross are in future to be disposed of in sealed containers, and contaminated materials are no longer being delivered to the site.
Medical tests have been carried out on all the employees at the factory. While these are not yet complete, indications so far are that no employees have suffered any ill effects from arsine gas.