(Beyond Pesticides, March 25, 2010) A new study finds that the absence of a maximum dose on some household pesticides labels leave consumers with the impression that “if a little is good, more is better.” According to the study that was presented at the 239th National Meeting of the American Chemical Society (ACS), label directions are written in a way that may result in consumers using excessive amounts of pesticides, subjecting their family and pets to increased exposures.
The new study, which was lead by California Environmental Protection Agency researcher Linda M. Hall, Ph.D., and her colleagues, finds that while minimum and maximum doses are clearly listed on labels for agricultural pesticides, labels for some household pesticides, such as para-dichlorbenzene (pDCB) mention the minimum amount for consumers to use but do not indicate the maximum.
Para-dichlorobenzene (pDCB) is the active ingredient in mothballs and other products used to protect silk, wool, and other natural fibers against moths and beetles; caged birds against lice and mites; mildew prevention; and is also used in air fresheners and bathroom deodorizers. Exposure to moth repellents, which include other toxic chemicals such as naphthalene and camphor, can cause eye and respiratory irritation, headaches, confusion and even loss of appetite.
The authors’ review of pDCB labels found that manufacturers specify a minimum rate of application (such as ounces or pounds per cubic foot of storage space) and a minimum treatment time, but no information on the maximum amount for safe use. “While this label sets conditions to protect against the pest insects, it allows consumers to follow the old adage, ‘if a little is good, more is better’! Thus, there is no limit on the amount that may be used per cubic foot of storage space,” said Dr. Hall. “This might account, in part, for the high levels of pDCB seen among some consumers.”
According to Dr. Hall, there are several recent national studies that have shown that various groups, including African-Americans and Hispanics, are likely to have elevated blood levels of a variety of indoor air pollutants. “Very important among these indoor air pollutants is pDCB, the moth ball ingredient,” said Dr. Hall, “All uses of pDCB in California are residential. Therefore, it is important that labels clearly define conditions for safe use by untrained residential consumers.”
Likewise, the study found that labels on moth control products specify a minimum treatment time, typically advising that clothing be treated in a closed container for seven days. However, labels do not specify a minimum airing procedure to dissipate the pesticide that has seeped into the fabric. Fabrics absorb high concentrations of moth repellants and, according to a 2008 study, can retain these concentrations even after prolonged airing. Napthalene and pDCB in moth repellents are readily adsorbed through the skin, and exposure comes from breathing in vapors and through wearing clothes exposed to these repellents.
“Thus, the consumer, following label instructions, might take clothing saturated with pDCB fumes directly from storage and wear it immediately,” Dr. Hall said. “Because no airing conditions are specified, consumers who find the pDCB odor unpleasant and do air clothing, might air it indoors, further contributing to human exposure to this substance.”
Vague pesticide labeling is not only found in pDCB products. Yesterday, Beyond Pesticides reported that EPA will begin reviewing labels for flea and tick pesticide products for cats and dogs, requiring manufacturers to make instructions clearer to prevent product misuse. In the next several months, new instructions and warnings are expected to appear on product labels.
Another example of consumer’s excessive pesticide use is with weed-and-feed products. A survey conducted in 2004 showed only 53% of households read and follow the label carefully when using pesticides and fertilizers. The U.S. Environmental Protection Agencies (EPA) acknowledges that homeowners often purposely overuse a product by thinking that more is better. Over-application of pesticides increases human health risks and the potential of harmful nontarget exposure through drift or runoff, but is ignored by EPA’s regulatory process in risk assessment and management calucations.
While it is wise to be aware of the limitations of current label instructions in order to use pesticide products in ways that minimize exposures, Beyond Pesticides recommends to the public to abandon poisonous chemicals and instead practice non-toxic methods of pest management and use least-toxic chemicals where possible.