Ask an Eco-Expert

Chlordane risks

My wife and I recently bought a wood home (built in 1919). About twenty years ago, it was treated for termite infestation with chlordane. We now hear that chlordane is no longer used. Should we worry about its presence in our home?

–Karl Jacoby, Providence, RI

Chlordane has been banned for all uses in the United States since 1988; however, manufacture for export still continues. According to the Agency for Toxic Substances and Disease Registry, chlordane was used as a pesticide on agricultural crops, lawns, and gardens and as a fumigating agent in the United States from 1948 to 1988. Chlordane is bioaccumulative (it builds up in our food chain) and remains in our food supply because of its use on crops in the 1960s and 1970s.

Because of cancer risk, evidence of buildup in human body fat, persistence in the environment, and danger to wildlife, the U.S. Environmental Protection Agency prohibited chlordane use on food crops and phased out other above-ground uses between 1983 and 1988. During those years, the only approved use was around home foundations to control termites.

Chlordane breaks down very slowly and can remain in soil for more than twenty years. It has been shown to persist in the air of some homes that were treated thirty to forty years ago.

Chlordane can enter the body through the lungs and through skin contact with contaminated soils. Most of it leaves the body in a few days, but chlordane can also be stored in body fat. Chlordane and its breakdown products in blood and fat can be measured as an indication of exposure.

Chlordane affects the nervous system, the digestive system, the endocrine system, and the liver. Breathing air containing high concentrations of chlordane vapors can cause headaches, irritation, confusion, weakness, and vision problems, as well as upset stomach, vomiting, stomach cramps, diarrhea, and jaundice.

A simple soil test will reveal if chlordane may be affecting the indoor air quality of your home. Your local health department will have a list of qualified laboratories. If you discover that your basement or crawl space has a contaminated soil floor, consider removing the soil and installing concrete and/or using vents or fans to exhaust the contaminated air, especially if the basement is part of the return air supply system. Chlordane that was applied in a broadcast fashion might have come into contact with the wood structure; in this case, consider sealing any interior wood to prevent further outgassing into your home.

Water-efficient dishwashing

Does washing all of our dishes by hand every day (with the water constantly running) save more water than using a new dishwasher twice per week (six gallons per load)? My husband and I would appreciate it if you would help settle this argument.

–Kate Morris, via e-mail

Whoever said the dishwasher is more efficient wins! Late-model dishwashers are actually pretty water-efficient. On average, dishwashers use between eight and fourteen gallons of water for a complete wash cycle, so your six-gallon model is very good. If you let the water run while you wash dishes, washing the same amount of dishes by hand uses about fifteen gallons.

If you don’t leave the water running, nothing is more efficient than washing dishes by hand. Fill a container or the sink with soapy water and then do the same with clean water to rinse them, or wash all your dishes and then turn on the faucet and rinse them all at once.

To improve your dishwasher’s water efficiency, remove excess debris from dishes before loading them (use a rubber scraper), run the dishwasher only when full, set it on short or light-soil cycles, and use the water-saving feature.

Toxic countertops?

Is there any toxic outgassing from solid-surface countertops (acrylic or polyester) such as Corian by DuPont?

–Barbara Claydon, via e-mail

Solid-surface countertops are made from thermoset plastic, which does not outgas.

There are two types of plastic: thermoplastic and thermoset. Both are made from chains of basic molecules, but the thermoplastic chains remain detached and separable, whereas the molecules of thermoset plastics are tightly bonded in web-like structures. The structure of thermoplastics allows them to be soft and bendable, and it also permits harmful vapors to outgas. Thermoset plastics are hard and brittle, so they break when bent and don’t outgas.

While solid-surface countertops are safe, they may be mounted on particleboard, which outgasses formaldehyde. For a simple solution, cover the exposed particleboard with heavy-duty aluminum foil or sturdier foil-backed kraft paper, and seal the edges with foil tape.

Is polar fleece safe?

Polyester fleece, also known as polar fleece or micro fleece, seems to be the only fabric that really insulates and repels dampness. Even wool (my first choice) does not offer the combination of insulation and lightness. Just how dangerous is this fabric to the human body, and what are its chemical components?

–Cheryl Brewer, Portland, OR

Polyester fleece is thermoplastic (see countertops question, above, for explanation), which means it can outgas because the molecules are separable.

Polyester fibers are known to cause eye and respiratory-tract irritation and acute skin rashes, but I want to emphasize that polyester fleece is way down near the safe end on the scale of toxic­ity. Many people don’t experience any ill effects from wearing fleece, but you might consider wearing a cotton layer next to your skin to prevent rashes.

We can compare natural wool with petrochemical-based polyester fleece and say that wool is natural, renewable, and biodegradable, and that polyester fleece is synthetic, nonrenewable, and doesn’t biodegrade. But the bottom line comes down to making educated choices to fulfill our daily needs.

If you have eco-questions, please write us at Natural Home, 201 E. Fourth St., Loveland, CO 80537-5655; or email

Need Help? Call 1-800-234-3368