The investigation was designed to determine the comparative value of certain washing agents in removing radioactive contamination from workers' hands, and was carried out at a production factory processing radioactive materials. Where radioactive materials are handled clean liness of the hands is of vital importance for the protection of the employee and for the manufacture of a product of extreme purity. At this factory those working in contact with radioactive materials are provided with a complete change of clothing to be worn at all times in the factory and have to undergo a precise and definite washing procedure. When they actually enter an area where radioactive substances are encountered extra protective garments are provided. These consist of an overall of a boiler-suit type, a cap, rubber surgeon's boots, and plastic gloves. On leaving the area the gloves are washed and removed, after which the hands are scrubbed thoroughly with soap and water. The overall, cap, and boots are then removed and, before finally leaving the change room attached to the area, the hand washing is repeated, using a proprietary cleanser (cleanser A in the investigation). On completing the day's work and before donning their own clothing, employees remove the special factory clothing and pass through a shower-bath. Their hands are checked on machines to determine their degree of radioactive contamination. This has come to be known as hand-monitoring . If hand-monitoring, which is carried out on an alpha hand-counting instrument (Type 1024), shows any contamination above a certain maximum permissible level the hands are washed again until the contamination has been removed.