“Ironic, isn’t it?” said Michael Braungart, the German chemist who co-wrote “Cradle to Cradle,” the best-selling sustainable design book, and co-founded the U.S. design consultancy McDonough Braungart Design Chemistry. “The color green can never be green, because of the way it is made. It’s impossible to dye plastic green or to print green ink on paper without contaminating them.”

Image Models walked around an iceberg for Chanel’s show at Paris Fashion Week. Credit... Ian Langsdon/European Pressphoto Agency

This means that green-colored plastic and paper cannot be recycled or composted safely, because they could contaminate everything else. The crux of the problem is that green is such a difficult color to manufacture that toxic substances are often used to stabilize it.

Take Pigment Green 7, the commonest shade of green used in plastics and paper. It is an organic pigment but contains chlorine, some forms of which can cause cancer and birth defects. Another popular shade, Pigment Green 36, includes potentially hazardous bromide atoms as well as chlorine; while inorganic Pigment Green 50 is a noxious cocktail of cobalt, titanium, nickel and zinc oxide.

If you look at the history of green, it has always been troublesome. Revered in Islamic culture for evoking the greenery of paradise, it has played an accident-prone role in Western art history. From the Italian Renaissance to 18th-century Romanticism, artists struggled over the centuries to mix precise shades of green paint, and to reproduce them accurately.

Even if they succeeded, the results often faded or discolored, as did green dyes. When the 19th-century British designer William Morris created wallpapers inspired by medieval tapestries, he copied the blue hues in the originals. But most of those “blues” were really greens, which had changed color over the years.