Lead compounds which, when mixed in a ratio of 1:1000 with 0.07 M hydrochloric acid and stirred for 1 hour at a temperature of 23°C ±2°C, exhibit a solubility of 5 per cent or less (see ISO 3711:1990 "Lead chromate pigments and lead chromate-molybdate pigments - Specifications and methods of test") are considered insoluble and are not subject to these Instructions unless they meet the criteria for inclusion in another hazard class or division.