Pesticide abandoned indoors (C) Daniel FriedmanPesticide Exposure in buildings

  • PESTICIDE EXPOSURE HAZARDS - CONTENTS: Health effects of exposure to pesticides in buildings. Exposure to common pesticides used indoors including Dursban and Lorsban, and Chlordane in older homes.
  • How to reduce indoor exposure to pesticides
  • POST a QUESTION or READ FAQs about pesticide exposure in buildings: detection, testing, hazard reduction

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Indoor pesticide exposure: here we describe the detection of and risks of exposure to pesticides applied indoors in buildings. We discuss methods to reduce indoor pesticide exposure as a step in improving health and indoor air quality in homes. Our page top photo shows an abandoned pesticide bottle found during a home inspection.

When we find old pesticide containers indoors we caution home buyers that a previous owner may have been applying chemicals without proper expertise. Read the label and use pesticides as directed.

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Pesticide Indoor Exposure Hazards & Health Effects

Bug on the garage door (C) Daniel FriedmanThis article includes excerpts or adaptations from Best Practices Guide to Residential Construction, by Steven Bliss, courtesy of Wiley & Sons.

Watch out: OPINION: don't panic about insects or bugs that you may see on or around your home.

A single bug like the one shown at left (clambering around on our garage door) does not merit a declaration of chemical warfare. Most insects seen on or around homes are harmless and should not be attacked.

The health risks to humans from overdoing chemical sprays and treatments applied in a panic can be significant.

Worse, misapplication of pesticides inside the home can lead to serious indoor health hazards for the building's human or pet occupants.

Termite activity on a foundation(C) Daniel FriedmanOn the other hand, as our photo at left (termite mud tubes) illustrates, even with care to avoid or fix building leaks (a key attractant to classes of termites, carpenter ants, and other wood destroying insects), is not always enough.

Sometimes it may be necessary to consult with a professional pest inspector or pesticide applicator. See INSECT INFESTATION / DAMAGE for details about preventing or correcting problems from wood destroying insects.

As stated in Best Practices Guide to Residential Construction:

Pesticides are a special class of organic chemicals designed to kill living organisms. In addition to the compounds used in the home and garden, the class of chemicals regulated as pesticides also include kitchen and bath disinfectants, flea and tick products, and swimming pool chemicals.

In most cases, both the active ingredient targeted to one or more pests and the “inert” carriers are organic chemicals that are toxic to humans.

Studies indicate that up to 80% of most people’s exposure to pesticides occurs indoors and that measurable levels of up to a dozen pesticides have been found in the air inside homes.

Because of its widespread use for over 30 years, more than 80 percent of Americans already have traces of Dursban in their bodies, according to the Centers for Disease Control. Another study found Dursban in the carpet dust of 67 percent of homes surveyed.

Also, remember that a pesticide found “safe” to use today may be determined to be unsafe tomorrow. Chlordane, the most widely use termiticide for decades, was banned in 1988 because of its toxicity to humans and its persistence in the environment. It was largely replaced by Dursban (chlorpyrifos), an organophosphate.

Dursban became the most widely used pesticide in the United States until it was phased out starting in 2000, along with the popular pesticide diazinon, because of the risks they posed to humans, especially to the growth and nervous system development of children.

Health Effects of Exposure to Pesticides

Signs of risk of termite attack (C) Daniel Friedman

Our photo (left) shows drill marks we found in the rim joist of an older home in the Hudson Valley of New York.

As we explain in detail at INSECT INFESTATION / DAMAGE, these drill marks were evidence of an amateur attempt at pesticide application: the location, irregularity, angle, and other details of these drill marks made us nervous.

We tested a sliver of this wood and found that it was still contaminated with Chlordane - misapplied on the building interior.

There are nearly 900 pesticides registered for use in the United States. Nearly all are at least moderately toxic to humans and pets and many are highly toxic.

Symptoms of overexposure to pesticides include irritation to the eyes, nose, and throat, headaches, blurred vision, nausea, loss of coordination, muscular weakness, and damage to the central nervous system, liver, and kidneys.

Every registered pesticide has a “signal” word on the label, ranking the level of toxicity to humans, as follows:

  • Danger—Poison: highly poisonous to humans or other animals
  • Danger: poisonous or corrosive
  • Warning: moderately hazardous
  • Caution: least hazardous

Some of the more problematic pesticides used in and around households include:

  • Organophosphates and carbonates. These two classes of chemicals, including Dursban and Lorsban, kill insects by disrupting their nervous systems. Studies indicate that they affect the birth weight and neural development of infants.

    From 1993 to 1996, nearly 63,000 reports were made to U.S. poison control centers about residential exposures to organophosphates, according to the U.S. EPA. Almost 25,000 of these incidents involved children under 6, who are particularly vulnerable to organophosphate poisoning and at least 482 resulted in hospitalization.
  • Mothballs - human exposure hazards: Mothballs contain either of the chemicals paradichlorobenzene or naphthalene. Paradichlorobenzene is classified as a possible human carcinogen by the EPA, and its vapors can irritate skin, eyes, and the respiratory tract. Large doses can damage the liver.

    Mothballs are not intended to be placed in open spaces such as rooms, closets, or vehicles. Rather they should be used in an airtight space such as a clothes storage bag. [7]

    Mothballs are fumigants that will dissolve or sublime at lower temperatures; mothballs thus work by a process of sublimation - the solid ball of chemicals converts directly to a gas that enters the air nearby. [2][7] But believe it or not mothballs or moth crystals may also be a child hazard if eaten - as has happened. [3][6][7]

    Symptoms of exposure to naphthalene include headache, nausea, dizziness, and difficulty breathing. Paradichlorobenzene is also a potential hazard, although typically less so compared to naphthalene. ... Eating just one mothball containing naphthalene can damage a young child’s red blood cells.... [7]

    Exposure to naphthalene promotes hemolytic anemia, associated with fatigue in mild cases and acute kidney failure in severe cases. Poisonings of infants have been reported after dressing the children in clothing stored in naphthalene mothballs.

How to Reduce Indoor Exposure to Pesticides

When possible, the best approach is to find non chemical approaches to pests. When chemicals must be used, choose the least toxic option, and use it outdoors, if possible, and away from areas used by pets and children who will track it back into the house.

  • Use insect-resistant construction materials and techniques. The use of termiticides can be reduced or eliminated by careful detailing of entry points, and by using alternative building materials, such as steel, masonry, concrete, insulating concrete forms (ICFs), or treated lumber. Borate-treated lumber is nontoxic to humans and very effective against termites and carpenter ants as long as it is not exposed to regular wetting.
  • Use non chemical methods of pest and weed control. Since outdoor pesticides and herbicides invariably end up indoors on carpets and in the air, it is prudent to reduce the use of chemicals indoors and out. Options include integrated pest management, biological pesticides, and planting disease-resistant plants.
  • If using chemicals, choose the least toxic. Look for products with the signal word “warning” or “caution” rather than “danger.” Baits and traps are better than sprays or “bug bombs.”
  • Read the label and closely follow instructions. If you must handle pesticides, wear gloves and long sleeves and avoid breathing the vapors. Always keep these chemicals away from children. Carefully follow directions with regard to concentration, protective gear, and restricting access to treated areas. Always ventilate the area well after use, and mix or dilute chemicals outdoors if possible.
  • Dispose of unwanted pesticides safely. Most of these chemicals contain VOCs that will vaporize and get into the household air. If you cannot dispose of partially used containers, store outside the living space.
  • Minimize exposure to moth repellants. When used, place mothballs, moth repellent cakes or moth crystals in a well-sealed trunk or other container that can be stored in ventilated areas outside of the main living space, such as attics or attached garages.
  • Minimize exposure to some air fresheners: Paradichlorobenzene is also the active ingredient in many air fresheners and should be avoided.
  • Pesticides in drinking water - pesticide contamination of drinking water wells - see PESTICIDE CONTAMINATION TEST for water testing advice.

-- Adapted with permission from Best Practices Guide to Residential Construction.

Reader Question: How can we get rid of an annoying mothball odor in our Condo?

We moved into a condo, which is a concrete block structure 3 months ago. Shortly after the move we began to smell moth balls. After following the smell we were able to find out that the unit above us displaced several moth balls throughout there unit, tightly sealed the unit up without air conditioning on(we live in Florida) and left for the summer.

As the smell increased in our unit we begged parties involved to rid the unit of the moth balls and air it out.

Finally this was done, however even though the smell appears to be gone sometimes, other times we can still smell a bad odor, sometimes now the odor is less mothball smell and just simply a bad odor.  We have tried everything and are desperate to solve the problem. Is it possible to get rid of this toxic odor?  Any help would be greatly appreciated. - B.P. 9/22/2012

Reply: How to get rid of mothball odors in buildings, contents, clothing, furnishings

Moth (C) Daniel Friedman

Indeed the odor from moth repellent products (paradichlorobenzene or naphthalene) penetrates many materials including even drywall and furnishings.

It can take quite a while for the smell to diminish.

At MOTHBALL ODORS we have included your question again in the FAQs section where we also have provided a detailed list of suggestions for getting rid of mothball odors, starting with ventilating the source area but adding other steps as well.

Please take a look at that article and let us know if questions remain.

The photo at left, though a white moth-like insect, is not a clothing-attacking moth, as you'll read at our mothball odor article.

More about odor sources, hazards, & solutions is at ODORS GASES SMELLS, DIAGNOSIS & CURE.



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