Typically, the polythene bags used to dispose of general household waste are coloured black. Why is that?
The answer is in the recycling, because while the contents of the bags tend to go straight into landfill, the sacks themselves are made from pellets obtained from previously used plastic.
“Most of the waste polythene that is used to make the sacks are different colours as you can see in the picture, so a finished sacks out of these granules would look terrible,” says Daniel Crampton, director of Regal Polythene , a British supplier.
“So black dye is added to the granules in the manufacturing stage as black is a dominant colour and this masks the various granules and turn the finished sack black.”