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Illnesses Associated With Use of Automatic Insecticide Dispenser Units --- Selected States and United States, 1986--1999

To control indoor flying insects, restaurants and other businesses commonly use pyrethrin and pyrethroid insecticides sprayed from automatic dispensing units. Usually placed near entrances, these units are designed to kill flying insects in food service or work areas. On May 18, 1999, the Florida Department of Health (FDH) was notified by the Florida Department of Business and Professional Regulation (DBPR) that during May 12--17, three persons developed pesticide-related illnesses associated with improperly placed automatic insecticide dispensers. After FDH conducted a follow-up investigation and notified CDC's National Institute for Occupational Safety and Health (NIOSH) of this event, surveillance data were reviewed to identify additional cases of pesticide-related illnesses associated with automatic insecticide dispensers. Data were provided by the Toxic Exposure Surveillance System (TESS), the California Department of Pesticide Regulation (CDPR), the Montana Department of Agriculture (MDA), the National Pesticide Telecommunications Network (NPTN), and the Washington State Department of Health (WSDH)*. This report describes cases, summarizes surveillance data for pesticide-related illnesses associated with automatic insecticide dispensers, and provides recommendations for safe dispenser use.

Case Reports

Cases 1--3. A 42-year-old cook working at a Florida restaurant developed a sore throat, dyspnea, headache, and dizziness on May 12, 1999, after a several-hour exposure to mist released from insecticide dispensers in the food preparation area. The insecticide dispensers had been installed on May 10, but it is unknown on what day the cook was first exposed. The cook removed the dispensers on May 12 and noted relief of his symptoms. However, the restaurant management reinstalled the dispensers on May 14, and on May 15, a 40-year-old male customer developed headache and shortness of breath within 1 hour of entering the restaurant. These symptoms lasted approximately 4 hours. On May 17, approximately 45 minutes after leaving this restaurant, a 47-year-old male customer experienced a sharp burning sensation in his left eye and noted swelling, redness, and irritation of the eyelid that persisted approximately 24 hours. The implicated pesticide dispenser was within 6 feet of the booth where this customer had been sitting, and it faced his left eye. This person reported his symptoms to DBPR on May 18. None of the three persons sought medical attention for their symptoms. The active ingredients released by these dispensers were pyrethrin and piperonyl butoxide.

Case 4. On August 20, 1995, a 17-year-old male restaurant employee in California was changing the cartridge of an automatic insecticide dispenser. When he closed the dispenser panel, the firing mechanism was activated and discharged a pyrethrin-containing mist into his right eye. The employee immediately experienced burning in the eye and promptly sought medical attention at the emergency department of a local hospital. He was diagnosed with chemical conjunctivitis and treated symptomatically.

Surveillance Data

TESS is maintained by the American Association of Poison Control Centers and collects poisoning reports submitted by approximately 85% of U.S. poison control centers (1). A review of TESS data from 1993 through 1996, the most recent years for which data are available, identified 54 cases of pesticide-related illnesses associated with automatic insecticide dispensers; suicides and intentional misuse/abuse were excluded. Among the 42 cases for which specific age information was available, the median age was 22.5 years (range: 3--73 years). Among the 53 cases for which sex was known, 27 (50%) were male. Twenty (37%) cases were work-related. In all cases, pyrethrin/piperonyl butoxide was the responsible insecticide.

During 1986--1999, 43 cases of acute pesticide-related illnesses associated with automatic insecticide dispensers were reported to CDPR (32 cases), MDA (four cases), FDH (three cases), NPTN (two cases), and WSDH (two cases). Age, sex, and state of occurrence for these cases were compared with those from the TESS database, and no overlap with TESS data was found. Thirty-five (81%) of these cases were in persons exposed while at work, including seven whose exposure occurred during dispenser cartridge replacement or attempts to service faulty dispensers. Seven (16%) cases were in persons exposed while they were customers in restaurants, and one was a movie theater customer. For the 27 with age data available, the median age was 40 years (range: 17--68 years); for the 38 with information on sex, 23 (61%) were women. Resmethrin, a pyrethroid insecticide, was implicated in three cases; the remaining 40 were exposed to pyrethrin/piperonyl butoxide. Most insecticide dispenser-related illnesses identified in the non-TESS data occurred when the dispensers were improperly placed too close (i.e., <12 feet) to food handling, dining, or work areas; were placed where ventilation currents entrained the mist to such areas; and/or were serviced by persons unfamiliar with proper maintenance of these units.

Among the 94 pyrethrin/piperonyl butoxide-exposed cases in the combined surveillance data, signs and symptoms for 36 (38%) involved the eye; 34 (36%), the neurologic system; 26 (28%), the respiratory system; 23 (24%), the gastrointestinal system; 20 (21%), the nose and throat; 10 (11%), the skin; and eight (9%), the cardiovascular system. Some persons experienced signs and symptoms in more than one system. Among the three resmethrin-exposed cases, reported signs and symptoms included pruritus, throat irritation, nausea, vomiting, diarrhea, headache, burning sensation in the lungs, and cough.

Reported by: O Shafey, PhD, Bur of Environmental Epidemiology, Florida Dept of Health. L Mehler, MD, California Dept of Pesticide Regulation. L Baum, Pesticide and Surveillance Section, Washington State Dept of Health. Office of Pesticide Programs, US Environmental Protection Agency. Div of Environmental Hazards and Health Effects, National Center for Environmental Health; Div of Surveillance, Health Evaluations, and Field Studies, National Institute for Occupational Safety and Health; and an EIS Officer, CDC.

Editorial Note:

This report is the first to document pesticide-related illnesses attributable to automatic insecticide dispensers. Automatic insecticide dispensers are registered by the U.S. Environmental Protection Agency (EPA) for use in the restaurant industry and in other public settings, including schools, hotels, offices, supermarkets, hospitals, day-care centers, and long-term--care facilities (e.g., nursing homes). When used properly, automatic insecticide dispensers reduce the number of flying insects. However, given the dispensers' widespread use and potential for malfunction and/or improper use or maintenance, these units may pose a public health hazard.

Insecticide dispensers of the type described in this report are typically calibrated to spray automatically a fine mist of 50--100 mg of insecticide (consisting of approximately 0.5%--1.85% pyrethrin or resmethrin, along with other active and inert ingredients) every 15 minutes, 24 hours per day. Pyrethrins are insecticides derived from the oleoresin extract of dried chrysanthemum flowers (pyrethrum) (2). Piperonyl butoxide (either alone or combined with n-octyl bicycloheptene dicarboximide) often is added to pyrethrin products to inhibit microsomal enzymes that detoxify pyrethrins (2). Although pyrethrins (classified by EPA as acute toxicity category III compounds§) have little systemic toxicity in mammals, they possess irritant and/or sensitizing properties that can induce contact dermatitis, conjunctivitis, and asthma (2,3). Anaphylactic reactions (2) and gastrointestinal symptoms (4) related to inhalation of and cutaneous exposure to pyrethrin also have been reported; however, no previously published reports were identified associating pyrethrin exposure with reported cardiovascular (i.e., tachycardia, chest pain, and palpitations) or neurologic (i.e., headache, dizziness, malaise, altered taste, and lip numbness/burning) signs and symptoms. Resmethrin is a pyrethroid, a class of synthetic insecticides chemically similar to natural pyrethrins (2) and is classified in acute toxicity category III. Pyrethroids are reported to induce abnormal skin sensation, dizziness, salivation, headache, fatigue, vomiting, diarrhea, irritability to sound and touch, and other central nervous system effects (2,5).

The findings in this report are subject to at least two limitations. First, the surveillance systems that identified cases are passive and may have missed some acute pesticide-related illnesses. Second, lack of detailed information on incidents recorded in the surveillance data may have precluded identification of additional risk factors for insecticide dispenser-related illnesses.

Effective flying insect control can be achieved through nonchemical integrated pest management practices (e.g., proper sanitation practices by employees and installation of air curtains and screens). However, if automatic insecticide dispensers are used, they should be installed according to manufacturer labeling instructions. Warning stickers on dispensers should be considered, installation near supplied-air ducts should be avoided, and timers should be set to dispense insecticide during nonbusiness hours (6). Dispensers used in locations frequented by the public should be installed and serviced by commercial pest control operators. Although they are not required by EPA, persons servicing these devices should use personal protective equipment (i.e., chemical-resistant gloves and goggles designed to provide splash protection).


  1. Litovitz TL, Smilkstein M, Felberg L, Keil-Schwartz W, Berlin R, Morgan JL. 1996 report of the American Medical Association of Poison Control Centers Toxic Exposure Surveillance System. Am J Emerg Med 1997;15:447--500.
  2. US Environmental Protection Agency. Recognition and management of pesticide poisonings. 5th ed. Washington, DC: US Environmental Protection Agency, 1999.
  3. CDC. Illnesses associated with occupational use of flea-control products---California, Texas, and Washington, 1989--1997. MMWR 1999;48:443--7.
  4. Paton DL, Walker JS. Pyrethrin poisoning from commercial-strength flea and tick spray. Am J Emerg Med 1988;6:232--5.
  5. Hayes WJ, Laws ER, eds. Handbook of pesticide toxicology. Vol 2. San Diego, California: Academic Press, Inc., 1991.
  6. Anderson SR. Assessment of the health risks and handling of products used in food service establishments. J Envir Health 1985;47:200--1.

* The data from TESS, NPTN, and MDA were provided by the U.S. Environmental Protection Agency (EPA). EPA and several state health departments collaborate with NIOSH and CDC's National Center for Environmental Health to conduct surveillance of acute pesticide-related illness and injury.

Comparable information on the circumstances of incidents is not available in the TESS data.

§ EPA classifies all pesticides into one of four acute toxicity categories based on established criteria (40 CFR Part 156). Pesticides with the greatest toxicity are in category I, and those with the least are in category IV.

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