Tox Free Inc.

Good intentions may result in bad health

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Courtesy of Tox Free Inc.

President Obama’s stimulus investments in home energy efficiency may have the unintended consequence of increasing future medical costs. The stimulus bill contains $1500 tax credits for homeowners who install energy efficient doors, windows, and/or insulation. Studies in both the United States and England have shown that these home upgrades can reduce air infiltration by 50% in older homes, and as a consequence double the concentrations of indoor pollutants. According to the USEPA many pollutants found in indoor air are 9 times higher than in outdoor air. Chemicals such as formaldehyde, volatile organic compounds (VOCs), carbon monoxide and radon are commonly found in many homes and are recognized by most homeowners. However, many older homes that would benefit the most from these renovations may have vapors of organochorine insecticides in indoor air from termite treatment decades ago. Efforts to decrease infiltration of outside air would increase occupant exposure to indoor pollutants.

These insecticides were used almost solely for termite protection between 1950 and 1988 and USEPA estimates that 30 million homes were treated. Once applied into the soil under the home these chlorinated compounds do not degrade but do slowly volatilize thru cracks in the concrete and openings around pipes into the air of the home. Depending on the location of insecticide treatment and the amount of ventilation of air in the home, indoor air concentrations can vary orders of magnitude. High levels of chlordane/heptachlor (200-2000 ng/M3) are found when treatment is beneath the home – under the basement floor, in the soil of an enclosed crawl space, or under concrete slab floors. As occupants inhale these vapors their livers convert these insecticides to more potent carcinogens and toxins (oxychlordane, heptachlor epoxide and dieldrin) that accumulate in their fat. The air concentration of chlordane compounds in their current and previous home will determine the amount of oxychlordane, heptachlor epoxide and dieldrin in their body.

For 15 years the author has specialized in measuring these insecticides in indoor air and frequently found high levels in homes 30-40 years after application. I have found that the concentration in the air, matches the type and severity of the symptoms in occupants. In a recent study, the Silent Spring Institute measured levels of hormone disrupting chemicals in air of homes in Cape Cod, Massachusetts and reported chlordane, heptachlor, or dieldrin in the air of 50-60% of the homes with levels 4-40 times the US Environmental Protection Agency (USEPA), and Agency for Toxic Substances and Disease Registry (ATSDR) risk-based guidelines for ambient air. Since termite infestation and treatment increase in warmer climates, these numbers could increase with homes located farther south (see map in website below). This investigation by Silent Spring Institute also illuminates the probability of various toxic/carcinogenic chemicals acting with additive effects.

Chlordane compounds do not damage cells directly by reacting with molecules but instead by binding to receptors of steroid hormones (hormone disruptors), especially estrogen receptors. These estrogen receptors regulate many processes in many organs of the body. Estrogen receptors are located throughout the human brain and scientists have known for years that chlordane causes anxiety, depression, and behavioral, cognitive, and memory deficits. Recent studies demonstrate that chlordane compounds bind to estrogen receptors on human immune cells inducing phosphorylation of regulatory proteins and production of oxidants that damage cellular structures such as DNA and initiate chronic inflammation. These chronic inflammatory processes ultimately may cause insulin resistance, diabetes, respiratory infections, and possibly organic brain damage such as Parkinson disease. In animal studies, chlordane compounds have been determined to be some of the most potent carcinogens, resulting in their banning in 1988. Chlordane compounds in humans have been linked to increased rates of breast, prostate, testicular, leukemia, lymphoma, and brain cancer.

Two ways to remove these chlordane vapors from the air in your home is by ventilation with outside air or filtering indoor air through activated charcoal. Most major heating/air conditioning manufactures offer heat-exchange ventilation system that can be easily interfaced to your current ducting system. I have tested homes before and after such installation and have found at least a 10-fold reduction in the levels of insecticides.

For persons living in chlordane/heptachlor and/or aldrin/dieldrin treated homes, breathing these insecticides has the potential of causing greater adverse health effects than other more widely publicized pollutants. Occupants of homes built prior to 1988 should consider testing the air in their home before installing door, windows, and/or insulation, especially if occupants are currently experiencing neurological, immunological, or respiratory symptoms associated with chlordane/heptachlor exposure. Renovating basements for living areas may be ill-advised. These poorly ventilated spaces can have levels of insecticides 5-8 times those in ground level rooms.

Indoor air pollutants in homes are currently not regulated by the government. The Obama administration has emphasized preventive measures to reduce health cost. Highly cost-effect expenditures would be identifying toxic/carcinogenic chemicals in indoor air, publicizing their risk, and aiding in their removal. For more information on health effects of these insecticides and air testing see ( Dr. Cassidy provides free consulting and would be happy to answer your questions.

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