Illinois Pesticide Review
November / December 2008
In This Issue
Illnesses and Injuries Related to Total-Release Foggers
Total-release foggers (TRFs), sometimes called "bug bombs," are pesticide products designed to fill an area with insecticide and often are used in homes and workplaces to kill cockroaches, fleas, and flying insects. Most TRFs contain pyrethroid, pyrethrin, or both as active ingredients. TRFs also contain flammable aerosol propellants that can cause fires or explosions. This report summarizes illnesses and injuries that were associated with exposures to TRFs from 2001 to 2006 in eight states (California, Florida, Louisiana, Michigan, New York, Oregon, Texas, and Washington) and were investigated by the California Department of Pesticide Regulation (CDPR) and state health departments participating in the SENSOR-Pesticides program.
From 2001 to 2006, a total of 466 TRF-related illnesses or injuries were identified. These illnesses or injuries often resulted from inability or failure to vacate before the TRF was discharged, reentry into the treated space too soon after the TRF was discharged, excessive use of TRFs for the space being treated, and failure to notify others nearby. The findings indicate that TRFs pose a risk for acute, usually temporary health effects among users and bystanders. Three recent case reports are provided to illustrate common patterns observed in the surveillance data.
Case 1. In March 2008, a woman aged 38 years from Washington visited an emergency department with headache, shortness of breath, nausea, leg cramps, burning eyes, cough, and weakness after she was exposed to fumes from three TRFs (in 6-ounce cans) deployed nearly simultaneously by a downstairs apartment neighbor. One TRF each was set off in the crawlspace beneath the house, in the neighbor's apartment, and in the hallway. The building was an old house converted into apartments, with a single ventilation system connecting all apartments. The neighbor had verbally notified some of the tenants but not the patient. The patient recovered completely within 3 days, and the illness was classified as low severity. The TRF dispensed a toxicity category III pesticide product that contained permethrin and tetramethrin as active ingredients.
Case 2. In September 2007, a man aged 34 years who worked as a maintenance worker at an apartment complex in Michigan forgot to disarm the smoke detector before activating a TRF. Because the building elevator shuts down if a smoke detector is triggered, the maintenance worker (without respiratory protection) reentered the mist-filled apartment to disarm the detector. He had onset of cough and upper-airway irritation about 1 hour after exposure, contacted a poison control center, and did not seek additional medical care. His symptoms resolved within 24 hours, and his TRF-related illness was classified as low severity. He was exposed to a toxicity category III pesticide product with pyrethrins, cyfluthrin, and piperonyl butoxide as active ingredients.
Case 3. In August 2007, a man aged 54 years in California simultaneously set off nine TRFs in his small, 700-square-foot (6,000-cubic-foot) home. Each 1.5-ounce TRF can was designed to treat 5,000 cubic feet of unobstructed space and released a toxicity category III pesticide product containing cypermethrin. When the man returned 6 hours later, a strong odor prompted him to open the doors and windows and to vacate. Entering a second time 4 hours later, the man had onset of headache, dizziness, nausea, and vomiting. He visited an emergency department, where he was treated symptomatically for TRF-related illness with a nebulized anticholinergic bronchodilator; intravenous hydration; and intravenous medication for headache, nausea, and bradycardia. He completely recovered after 36 hours, and his illness was classified as moderate severity.
A total of 466 cases of acute, pesticide-related illness or injury associated with exposure to TRFs from 2001 to 2006 were identified. A total of 372 cases (80%) were classified as low severity, 84 cases (18%) were moderate severity, and nine cases (2%) were high severity. One death was classified by the Washington State Department of Health as suspicious. (This death occurred in a female infant aged 10 months who was put to bed the evening of the day her apartment was treated with three TRFs. The infant was found dead the next morning.) Twenty-one persons were hospitalized for 1 or more days (range: 1 to 35 days), and 43 persons lost time from work or other usual activities because of their illness or injury.
A total of 394 TRF exposures (85%) occurred in private residences. Among the 388 cases for which information was available regarding who activated the TRF, 197 of the illnesses (51%) involved the person who activated the TRF.
Among the 463 cases for which information on the implicated TRF product was available, 449 (97%) occurred in persons who were exposed to products with pyrethrin, pyrethroid, or both as active ingredients. Health effects most commonly involved the respiratory system (in 358 cases; 77%). The most common factors contributing to exposure included an inability or failure to vacate before the TRF discharged, early reentry, excessive use of TRFs for the space being treated, unintentional discharge of a TRF, and failure to notify others nearby.
TRFs are registered by EPA for use by homeowners and others. When activated, the TRF cans are designed to empty their contents completely. No special training or licensing is required to use a TRF. Numerous media reports in recent years have described injuries and property destruction resulting from explosions caused by activation of TRFs in the presence of ignition sources (for example, gas pilot lights and electrical appliances, such as air conditioners and refrigerators, that cycle off and on). However, this is the first report in the scientific literature to describe the range of exposure circumstances and acute health problems associated with TRF use.
The public should be warned about TRF dangers that explain the importance of reading and understanding the pesticide label, using the correct number of TRFs, and taking necessary precautions (for example, turning off ignition sources and promptly leaving the premises). TRF labels should be improved to make information easier to find and understand. Current TRF labels indicate the number of cubic feet that one container can treat effectively for pests, which requires the user to employ arithmetic to calculate both the volume of space to be treated and the number of TRFs needed to treat a space of that size. Use of delayed-release TRFs also might prevent illnesses and injuries by allowing the user to vacate the premises before the insecticide is released. Notices should be posted on the exterior of spaces where TRFs are used. Coinhabitants (and nearby neighbors, when multiunit housing is treated) also should be informed before a TRF treatment is started.
(Adapted by Phil Nixon from a Centers for Disease Control report on October 17, 2008. The entire report is available at http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5741a3.htm?s_cid=mm5741a3_e.)
Adjuvants are chemicals that do not possess pesticidal activity. Adjuvants are either premixed in the pesticide formulation or added to the spray tank to improve mixing or application or to enhance pesticidal performance. They are used extensively in products designed for foliar applications. Adjuvants can be used to customize the formulation to specific needs and compensate for local conditions.
The right adjuvant may reduce or even eliminate spray-application problems, thereby improving overall pesticide efficacy. Because adjuvants themselves have no pesticidal properties, they are not registered by the EPA. As a result, there is no set of standards for composition and quality, although some states have modified registration requirements for these chemicals and may require labels, technical data sheets, and efficacy information.
Before using any adjuvant, consult the pesticide label. Many registered pesticide products have very specific recommendations on their labels for use with one or more adjuvants. Failure to follow these instructions is as much a violation of the product label as inap-propriate use of the pesticide.
If you have questions about the specific properties of an adjuvant, contact the manufacturer before attempting to use it. Companies that produce adjuvants can provide labels, technical data sheets,
MSDSs, supplemental labeling, and promotional literature about their products.
Adjuvants are designed to perform specific functions, including wetting, spreading, sticking, reducing evaporation, reducing volatilization, buffering, emulsifying, dispersing, reducing spray drift, and reducing foaming. No single adjuvant can perform all these functions, but compatible adjuvants often can be combined to perform multiple functions simultaneously.
Much of the confusion surrounding adjuvants can be attributed to the lack of understanding of associated terminology. For example, many people use the terms "adjuvant" and "surfactant" interchangeably. These terms can refer to the same product because all surfac-tants are adjuvants; however, not all adjuvants are surfactants.
Surfactants, also called wetting agents and spreaders, physically alter the surface tension of a spray droplet. For a pesticide to perform its function properly, a spray droplet must be able to wet the foliage and spread out evenly over a leaf. Surfactants enlarge the area of pesticide coverage, thereby increasing the pest's exposure to the chemical. Surfactants are particularly important when applying a pesticide to waxy or hairy leaves. Without proper wetting and spreading, spray droplets often run off or fail to cover leaf surfaces adequately. Too much surfactant, however, can cause excessive runoff and reduce pesticide efficacy.
Surfactants are classified by the way they ionize or split apart into electrically charged atoms or molecules called ions. A surfactant with a negative charge is anionic. One with a positive charge is cationic, and one with no electrical charge is nonionic. Pesticidal activity in the presence of a non-ionic surfactant can be quite different from activity in the presence of a cationic or anionic surfactant. Selecting the wrong surfactant can reduce the efficacy of a pesticide product and injure the target plant. Anionic surfactants are most effective when used with contact pesticides (that is, pesticides that control the pest by direct contact rather than being absorbed systemically). Cationic surfactants should never be used as stand-alone surfactants because they usually are phytotoxic.
Nonionic surfactants, often used with systemic pesticides, help pesticide sprays penetrate plant cuticles. Nonionic surfactants are compatible with most pesticides, and most EPA-registered pesticides that require a surfactant recommend a nonionic type.
A sticker is an adjuvant that increases the adhesion of solid particles to target surfaces. These adjuvants can decrease the amount of pesticide that washes off during irrigation or rain. Stickers also can reduce evaporation of the pesticide, and some slow down the degradation of pesticides by sunlight. Many adjuvants are formulated as spreader–stickers to make a general-purpose product.
Extenders function like stickers by retaining pesticides longer on the target area, slowing evaporation, and inhibiting degradation by sunlight.
Plant penetrants have a molecular configuration that enhances penetration of some pesticides into plants. An adjuvant of this type may increase penetration of a pesticide on one species of plant but not another. Enhanced pen-etration increases the activity of some pesticides.
Compatibility agents are used when pesticides are combined with liquid fertilizers or other pesticides. Certain combinations can be physically or chemically incompatible, which causes clumps and uneven distribution in the tank. Occasionally, the incompatihle mixture plugs the pump and distribution lines, resulting in expensive cleanup and repairs. A compatibility agent may eliminate these problems.
Read product label directions carefully before adding a compatibility agent to a spray mix. You may wish to do a compatibility test in a quart jar to determine the stability of the mixture. After adding the desired pesticides and the compatibility adjuvant to the jar, shake the mixture and then check for clumping, separation, thickening, and heat release. Any one of these signs indicates an incompatibility problem.
Buffers or pH modifiers increase stability of mixed pesticides. Most pesticide solutions or suspensions are stable between pH 5.5 and pH 7.0 (slightly acidic to neutral). Above pH 7.0 (alkaline or basic), the pesticide may be subject to degradation. Once a pesticide solution becomes alkaline, the risk exists for the pesticide to degrade quickly. Buffers and acidifiers are adjuvants that acidify and stabilize the water in the spray tank. Buffers must be added to the tank-mix water first. The water must be neutralized or slightly acidified prior to adding pesticides and adjuvants.
Drift-control additives, also known as deposition aids, improve on-target placement of the pesticide spray by increasing the average droplet size. Drift reduction can be very important near sensitive sites and may well be worth the small reduction in efficacy that may result from the change in droplet size.
Defoaming agents reduce or eliminate the foam or frothy "head" that some pesticide formulations create in spray tanks. This is often the result of both the type of surfactant used in the formulation and the type of spray-tank agitation system. The foam usually can he reduced or eliminated by adding a small amount of a defoaming agent.
Thickeners increase the viscosity (thickness) of spray mixtures. These adjuvants are used to control drift or slow evaporation after the spray has been deposited on the target area. Slowing evaporation is important when using systemic pesticides because they can penetrate the plant cuticle only as long as they remain in solution.
Many factors must be considered when choosing an adjuvant for use in a pest-management program. Use only adjuvants manufactured and marketed for agricultural or horticultural uses. Do not use industrial products or household detergents with pesticides because they may interfere with pesticide performance.
Remember, there are no miracle adjuvants. It is generally wise to be skeptical of such claims as "keeps spray equipment clean" or "causes better root penetration" unless the manufacturer has supporting evidence to back up such claims. Make sure the adjuvant has been thoroughly tested and proven effective for your intended use. Test questionable products on a limited area before proceeding with full-scale use.
Certain pesticides and application procedures require certain types of adjuvants. Determine the correct type and use only an adjuvant of that type. For example, do not substitute an anionic surfactant when a nonionic surfactant is recommended. A particular pesticide label may require one or more adjuvants for a certain use yet prohibit any adjuvant for another use. Read the pesticide label carefully. Using an adjuvant is not always necessary. It is just as important to know when not to use an adjuvant as it is to know when to use one.
Spray adjuvants can contribute substantially to safe and effective pest control. Many spray adjuvants are available, each formulated to solve problems associated with a particular type of application. Check pesticide and adjuvant labels to make sure adjuvants are suitable for the site you plan to spray, the target pest, your equipment, and, of course, the pesticide you plan to use.
Remember, many pesticide products already contain an adjuvant. If a pesticide is already formulated properly for your crop, using an additional wetting agent, for example, may not give better spreading or coverage; instead, it could increase runoff, reduce deposit, and even severely damage the target plants.
(Adapted slightly from National Pesticide Applicator Certification Core Manual by Phil Nixon.)
Accidental exposure or overexposure to pesticides can have serious implications. The potential for pesticide accidents is real. While most of these pesticides can be used with relatively little risk (as long as label directions are followed), some are extremely toxic and require special precautions. Wearing protective clothing and equipment when handling or applying pesticides reduces the hazards or risk of pesticide poisoning. The hazard of pesticide poisoning is reduced because the chance of exposure is reduced.
When considering the hazard of using a pesticide, you need to consider both the toxicity of the pesticide and the exposure (where did you get it on yourself and how long did you leave it).
Understanding the toxicity of a product and the potential for personal exposure allows the hazard to be lowered. No matter how toxic a pesticide is, if the amount of exposure is kept low, the hazard can be held at an acceptably low level. The toxicity of a pesticide can't be changed, but the applicator can manage the exposure.
Nearly all pesticides are toxic. They differ only in the degree of toxicity. Because of this, pesticides are potentially dangerous to people if exposure is excessive. A pesticide product label has one of three signal words that clearly indicates the degree of toxicity associated with that product (Table 1). The safest products no longer have a signal word. The signal words indicate the degree of potential risk to a user, not the effectiveness of the product.
Along with the signal words, pesticide labels also include statements about route of entry and specific actions that must be taken to avoid exposure. Route-of-entry statements indicate the outcome that can be expected from exposure. For example, a pesticide label might read: "Poisonous if swallowed, inhaled, or absorbed through the skin. Rapidly absorbed through the skin and eyes." This indicates that the pesticide is a potential hazard through all three routes of entry, and that skin and eye contact are particularly hazardous. Specific-action statements normally follow the route-of-entry statement and indicate what must be done to prevent poisoning accidents. In the case of the pesticide discussed above, the statement might read: "Do not get in eyes, on skin, or on clothing. Do not breathe spray mist."
Routes of Exposure
Pesticides can enter the human body three ways: (1) by absorption through the skin or eyes (dermally), (2) through the mouth (orally), and (3) by breathing into the lungs (inhalation).
Dermal exposure results in absorption immediately after a pesticide contacts skin or eyes. Absorption will continue as long as the pesticide remains in contact with the skin. The rate at which dermal absorption occurs is different for each part of the body. The relative absorption rates are determined by comparing each respective absorption rate with the forearm absorption rate.
Relative absorption rates, compared to the forearm with an absorption rate of 1.0. It is easy to transfer pesticide residues from one part of the body to another. When this occurs, the applicator increases the potential for pesticide poisoning. For example, residues can be inadvertently moved from a hand to a sweaty forehead (4.2) or to the genital area (11.8). At this very high rate, the absorption of a pesticide is more dangerous than if it were swallowed! The speed of which it enters the body can be likened to that of direct injection by hypodermic needle into a vein.
Oral exposure may result in serious illness, severe injury, or even death if a pesticide is swallowed. Pesticides can be ingested by accident, through carelessness, or intentionally.
The most common accidental oral exposures occur when pesticides have been removed from their original containers and placed into an unlabeled bottle, jar, or food container. Children under age 10 are victims of at least half of the accidental pesticide deaths in the United States. If pesticides were managed properly, children would never touch them.
Follow these guidelines:
• Always store pesticides in their original, labeled containers.
• Never use the mouth to clear a spray hose or nozzle, or to begin siphoning a pesticide.
• Never eat, drink, or use tobacco until after leaving the work area and washing thoroughly.
Respiratory exposure is particularly hazardous because pesticide particles can be rapidly absorbed by the lungs into the bloodstream. Pesticides can cause serious damage to nose, throat, and lung tissue if inhaled in sufficient amounts. Vapors and very small particles pose the most serious risks.
Lungs can be exposed to pesticides by inhalation of powders, airborne droplets, or vapors. Handling concentrated wettable powders can pose a hazard if they are inhaled during mixing. The hazard from inhaling pesticide spray droplets is fairly low when dilute sprays are applied with low-pressure application equipment. This is because most droplets are too large to remain airborne long enough to be inhaled.
However, when high-pressure, ultra-low-volume (ULV), or fogging equipment is used, the potential for respiratory exposure is increased. The droplets produced during these operations are in the mist- or fog-size range and can be carried on air currents for a considerable distance.
(Information slightly adapted by Jim Schuster, Extension specialist, Pesticide Safety Education—plant pathology; from University of Nebraska Cooperative Extension EC97-2505-A, Signs and Symptoms of Pesticide Poisoning by Larry D. Schulze, Extension pesticide coordinator, Clyde L. Ogg, Extension assistant, pesticide training, and Edward F. Vitzthum, coordinator, environmental programs.)
NPIC Web Site Now Available
If you've called the National Pesticide Information Center (NPIC) with pesticide related-questions or if you've seen any of their many fact sheets, you know that they are such a great resource for "anything pesticide." They take calls and emails daily from pesticide-application professionals and homeowners alike and provide answers that are science-based and objective. NPIC is a cooperative agreement between the USEPA and Oregon State University.
Now their same great Web site is available in Spanish at http://npic.orst.edu/index.es.html.
In a recent email announcement, Kaci Angle, NPIC's project coordinator, wrote, "Last year, NPIC made services available over the phone in over 170 languages, and disseminated NPIC brochures and fliers in Spanish. Now that the Spanish website is operational, our next goal is to translate original NPIC publications (fact sheets, common pesticide questions) into Spanish."
They are looking for feedback. So, if you have ideas you'd like to share, contact them at firstname.lastname@example.org. You can also sign up for notification of new publications by emailing email@example.com. Be sure to type "subscribe" in the subject line.
9th Annual Pesticide Stewardship Conference
The Pesticide Stewardship Alliance is planning its 9th Annual Pesticide Stewardship Conference. Plan to escape the cold and attend this informative and educational event, February 22 to 24 in sunny Albuquerque, New Mexico.
Conference objectives: To serve as a forum for facilitating networking and cooperation among parties from around the world to improve stewardship program efforts—increasing effectiveness and efficiency through pesticide labeling, judicious application, container containment, waste minimization, and proper handling of empty containers and other agricultural plastics. TPSA seeks individuals with pertinent information from private companies, public entities, and organizations who are willing to share their stories, findings, and challenges. Network during the evening festivities, opening reception, and grand reception.
Conference symposia topics:
• agricultural plastics management
• empty-pesticide-container management
• international stewardship
• disposal of obsolete pesticides
• Web-distributed pesticide labeling
• pesticide-container-containment rule implementation
• label language for promoting stewardship/compliance
• soil-fumigation stewardship
Currently, there is a call for relevant posters and papers. Share your stewardship efforts with others or simply attend to learn a few ideas you can employ once you return home.
For more information, visit the conference Web site: http://tpsalliance.org. (Michelle Wiesbrook, from an email from Bonnie McCarvel, operations manager of The Pesticide Stewardship Alliance, 11/12/08.)
08–09 Commercial Clinic Schedule Released
The Pesticide Safety Education Program at the University of Illinois has released its clinic dates for the 2008–2009 season. The complete commercial clinic schedule can be found on our Web site at https://webs.extension.uiuc.edu/psep/training/clinics.cfm.
Schedule booklets may be picked up at your local U of I Extension office or ordered by calling (800)644-2123 or (217)244-2123. The booklets contain order information for study materials. You may register for clinics or order materials via our Web site or by calling the numbers above.
How current are the study materials on your bookshelf? A lot can change in a 3-year test cycle. Materials are revised from time to time, so we recommend that before training or testing you check for the latest revision date at our publications page, https://webs.extension.uiuc.edu/psep/publications/publications.cfm.
Schedule booklets were also mailed with the annual Illinois Pesticide License retest and renewal letters. As I write, I'm still waiting for mine. If for some reason it never arrives in my mailbox, I know where to look to check on my license status. The Illinois Department of Agriculture unfortunately no longer uses the Kelly Solutions Registration Database. In the past, I've written about this handy, searchable database found on IDA's Web site. You can now delete that link if you have it bookmarked. IDA's Web site now features a slightly different searchable database at http://www.agr.state.il.us/Environment/Pesticide/aplicatorsearch.php. It can be used by anyone to determine the license status of an Illinois-licensed pesticide applicator or operator. You may also still search for registered products, though the search options are less extensive than previously.
As a reminder, December 31 is the expiration date for Commercial, Commercial Not-for-Hire, Dealer, and Public licenses. Your letter will explain the necessary steps you should take to renew your license.
Information on license requirements and testing and training options will also be included in your letter. It can also be found on our Web site: https://webs.extension.uiuc.edu/psep/training/.