18. Holders of a Class A or Subclass B1, C4, C5 or D4 permit who store unprepared or undiluted Class 1, Class 2 or Class 3 pesticides must store them in premises having a containment works. The same applies to any person who stores a quantity equal to or greater than 100 litres or 100 kg of unprepared or undiluted Class 1, Class 2 or Class 3 pesticides for a period longer than 15 consecutive days.