They're hiding under your sink, deep in the basement and out in your garage. They seem to be multiplying and most of them are green, for gosh sakes!

They are cleaning products. We have one for every conceivable job: floors, walls, dishes, laundry, windows, bathroom porcelain and ceramic tiles, wooden decks, cement surfaces, silverware, one for car paint and another for the chrome, and on and on.

Whatever happened to just plain soap? Well, it seems it wasn't fast enough for our busy lives. And these new cleaners certainly are fast. Just spray and wipe or swish with a mop and the job is done.

If you want really fast general cleaning products, commercial ones like Formula 409, Simple Green and Windex clean faster than any soap and water could. This is because they contain small amounts, usually in the range of 2-6 percent, of some members of the most powerful grease-cutting class of chemicals known: the "glycol ethers."

Many people have heard of glycols, a class of chemicals used in antifreeze solutions in your car's radiator. Others may remember that ethers were used as anesthetics in the early 1900s. But the glycol ethers we will discuss are not at all like either glycols or ethers. Glycol ethers are in a class of their own.

Everyone has been exposed to the glycol ethers. You can't possibly have escaped. They are in paints, varnishes, stains, inks, brake fluids, perfumes, cosmetics, and, of course, a vast number of cleaning products. They mix with water and many water-based cleaners and paints contain them.

Heavy overexposure to the glycol ethers can cause anemia, intoxication (like alcohol), and irritation of the eyes and nose. In laboratory animals, low-level exposure to some of the glycol ethers has been shown to cause birth defects and can damage a male's sperm and testicles. Some of the common glycol ethers haven't been studied for reproductive hazards or cancer. But there is enough data for the New Jersey Department of health to state on its fact sheet that the most commonly used glycol ether (2-butoxyethanol) "may be a carcinogen in humans since it has been shown to cause liver cancer in animals." I agree.

You are exposed to the glycol ethers when you inhale them as the cleaner is used. If the cleaner does not also have a lot of perfumes or odorants, you know you are exposed because you can smell the chemical. If there are strong perfumes, the odor of the glycol ethers can be covered so that the water-based cleaner appears to have no chemicals solvents in it at all.

While you are inhaling them, you also may be exposed in another way as well. Most glycol ethers can silently penetrate your skin and enter your bloodstream without altering or damaging your skin, causing pain, or giving you any other warning.

If that were not enough, the glycol ethers also go through natural rubber gloves and many types of plastic gloves without changing their appearance. So while you are cleaning, you are being exposed both by inhaling the vapors as the cleaner evaporates and by exposure through your skin even if you are wearing gloves. These are reasons why even the 2-6 percent of these chemicals commonly in cleaning products can be significant.

The glycol ethers are all related to each other in a single chemical class. There are hundreds of them. We will look only at the first four members of the glycol ether class.

The first two glycol ethers (2-methoxy- and 2-ethoxy-ethanol) are so toxic that it is rare to see them in our products today. But if you were cleaning and doing household painting and repairs as I was from the 1970s to the early 1990s, these highly toxic glycol ethers were in most of the cleaning and paint products then. If you were working as an artist or teaching art during this period of time, those glycol ethers were in our products in large amounts. Some of the new "safer" water-based paints and printmaking inks contained glycol ethers in amounts as high as 30 percent.

People working with cleaning products, paints and inks in the 1970s through early 1990s were often regularly exposed to these skin-absorbing reproductive hazard chemicals. And it occurs to me, that it was at this time we also began to see the phenomenal rise in autism and learning difficulties in our offspring. I know every science writer seems to have a different theory about why these illnesses are on the rise, but I tend not to think the culprits are tiny amounts of pollutants in the environment or minuscule amounts of mercury in vaccinations. Not when we've used billions of pounds of glycol ethers and many other types of toxic solvents, evaporating them into homes where children and pregnant women often have 24-hour-per-day exposure.

Today your products are more likely to use the glycol ethers containing propyl and butyl groups which are presumably less toxic reproductive hazards, but toxic nonetheless. You are especially likely to be exposed to 2-butoxyethanol. Many manufacturers use 2- butoxyethanol because in 2004, the Bush administration's EPA took this glycol ether off of its list of Hazardous Air Pollutants (HAPs). Keep in mind a HAP chemical is one that can participate in smog reactions or damage the stratospheric ozone layer. The fact that butoxyethanol is not an air pollutant is unrelated to the toxic effects it may have on users.

This means if a manufacturer of a cleaning product wants to advertise its product as one that does not containing chemicals regulated by EPA, it is likely to use the butyl glycol ethers or propyl glycol ethers that never were on the list. And if the manufacture's definition of "green" is the absence of air pollutants, it may even tout these products as "green."

The problem is, of course, that I have greatly oversimplified the glycol ether problem in order to explain it. Actually there are dozens of other more complex glycol ethers and related chemicals like the glycol ether acetates that could be in your products. And there is almost no available toxicity data on many of these. Manufacturers can substitute these more complex glycol ethers that have the same dizzying number of names and synonyms.

And now, more and more often, I see manufacturers withholding the identities of their glycol ether solvents. For example, I have six years worth of material safety data sheets on All-Purpose Simple Green. Originally, it contained 6 percent 2-butoxyethanol which was about twice as much as many other fast cleaners did at that time. This is probably why it worked so well. Then the material safety data sheets showed the 2-butoxyethanol content had dropped to 3 percent. The latest MSDS indicates there is only about 1 percent of this glycol ether in it. But since the product cleans just as well as the original formula did, and because the MSDS now says there are other ingredients in the product that are not revealed, I have to suspect there are some of these other glycol ethers in the cleaner.

When a product cleans this fast, it ain't soap!

In fact, plain soap and water is a good substitute for the solvent-containing cleaners if you are willing to put a little elbow grease into the work and to rinse the soap from the surface after cleaning. But if you feel you must use a fast cleaner that can be sprayed on and wiped off in one operation, then provide some ventilation such as a window exhaust fan drawing air across your work area and exhausting it to the outside. Remember, don't use rubber or vinyl gloves since these are quickly penetrated by the glycol ethers without changing the glove's appearance. Purchase some nitrile plastic gloves and contact the manufacturer's technical service to find out how often you should change your gloves since the glycol ethers will penetrate even these gloves in time.