I once rented a flat in a beautiful old Victorian house that had suffered years of neglect and mistreatment by prior tenants. While living there, I did what I could to restore or at least clean up the original moldings and fireplace surround.

But because the entrance hall served my apartment and two others, I just walked through it, barely noticing that its floor had some kind of pattern in red and white faintly visible under years of accumulated grime.

Then one summer day, when the front door was wide open and the sunshine highlighted the grime, I decided I should at least mop the entrance floor. The mopping led to some scraping which slowly revealed a beautiful scarlet stripe bordering a cream, gold and green field.

I scraped carefully, because the photographic patterns printed on vinyl floors are paper thin and easy to damage. But I nicked the floor anyway, only to discover that the color didn't stop at the surface but apparently went all the way through the material.

Once I realized that, my scraper gave way to my belt sander, and in a couple of hours I had unearthed a real treasure -- a richly colored, inlaid floor with elaborate rosettes and an intricate border. Although the floor resembled inlaid wood, the pieces had no grain per se, but rather a fine marbled pattern. I was so used to seeing vinyl that it took me a while to realize that I had uncovered old linoleum.

What is linoleum?

To begin with, it's definitely not vinyl, although many people confuse the two and even call vinyl floors "linoleum." Vinyl is a petroleum product, made primarily from polyvinyl chloride (PVC), a known carcinogen. Also, the PVC manufacturing process releases highly toxic dioxins, another class of carcinogens that can also cause nervous and thyroid disorders.

Although it is possible to recycle vinyl, most of it ends up in landfills, and it is not biodegradable. As one vinyl manufacturer boasted, "Vinyl is final."

Linoleum, on the other hand, is a composite made primarily of linseed oil, pine rosins (solidified pitch such as amber), and "wood flour" (extremely fine sawdust). The mixture, which can be colored with environmentally benign pigments, is rolled into sheets and then cured in an industrial oven. The finished sheets can be backed with jute, a natural fiber.

Linseed oil is pressed from the seeds of the flax plant (genus Linum), the same seeds that people eat to aid digestion and lower their cholesterol. Flax is grown around the world for its fiber, the source of linen, as well as for its seed. A hearty, fast-growing plant cultivated since prehistoric times, flax needs little or no fertilizer or pesticide protection.

Pine trees are also abundant and fast growing, and the hardwoods used to make the wood flour can be sustainably harvested. Once the linoleum is cured, the wood-based ingredients are non-toxic and do not outgas. All the ingredients of linoleum are biodegradable and potentially recyclable. Ingredients do vary from manufacturer to manufacturer, so check for the most environmentally friendly product.

Although linseed oil is cured to form a hard-but-flexible surface in the oven, it continues to cure for decades. Since it cures by oxidation, the curing process makes its surface anti-bacterial and anti-allergenic, so linoleum is the preferred flooring for many hospitals, clinics and homes for people with allergies.

Linoleum comes in a wide variety of colors and patterns that invite creativity on the part of the designer. Like vinyl flooring, it's available in both sheets and tiles. However, while do-it-yourselfers can install many types of vinyl tiles, linoleum manufactures strongly recommend professional installation for their products because they require specialized glue and troweling techniques. Some manufacturers do, however, provide snap-together, floating floors for homeowner installation.

Installed, linoleum cost two to three times as much as vinyl, which is why vinyl largely displaced linoleum in the 1950s. But in today's economic environment, where our homes are dwellings and not merely investments, natural, durable linoleum is making a comeback.

Manufacturers claim that linoleum will last 40 years, but my experience with that old Victorian indicates that with proper maintenance it could last even longer in your ecological house.