Our eco-shop has the following on the homepage about linoleum: "This natural, elastic floor covering is made, as its name already suggests, besides linseed oil (linum = flax and oleum = oil) from natural resins, wood flour, limestone flour, and color pigments. It is thanks to its natural ingredients that there are no nasty surprises with emitted harmful substances such as formaldehyde, solvents, and plasticizers—neither during installation nor in use—and that it additionally has antibacterial and slightly fungicidal effects. It is no coincidence that it is often found in hospitals, medical practices, and similar places. The increased hygiene requirements there are also met by the seamlessness—which, unlike tiles as another wipeable smooth surface, is without joints." I think that already sounds very natural and at the same time nicely robust. Suitable for 4 boys' rooms.