Extreme densities of industrial plastic pellets were found on 18 October 1989 on the beach north of IJmuiden. Nearly all pellets were new and of the same shape and whitish colour, and are therefore likely to originate from a single source. Figures of contents of four sample sites of 1 metre length are given in the table (Numbers of new and old industrial plastic pellets, fragments of users plastics, small tarballs and paraffine (?); samples taken in areas with low density (’laag’), average density (’gemiddeld’) and high density (’hoog’)). The average density over the total length of beach searched for plastics (3 km) is estimated at about 3000 pellets (96 grams) per metre. This means that this stretch of beach alone received about 9 million pellets, with a total weight of 288 kg.