# ENVIRONMENTAL HEALTH PERSPECTIVES ENVIRONMENTAL HEALTH PERSPECTIVES

National Institutes of Health U.S. Department of Health and Human Services 

# Acute Pesticide Illnesses Associated with Off-Target Pesticide Drift from Agricultural Applications — 11 States, 1998–2006 Soo-Jeong Lee, Louise Mehler, John Beckman, Brienne Diebolt-Brown, Joanne Prado, Michelle Lackovic, Justin Waltz, Prakash Mulay, Abby Schwartz, Yvette Mitchell, Stephanie Moraga-McHaley, Rita Gergely, Geoffrey M Calvert doi: 10.1289/ehp.1002843 (available at http://dx.doi.org/) Online 6 June 2011 ehponline.org 

# ehp

## 1

Acute Pesticide Illnesses Associated with Off-Target Pestic ide Drift from Agricultural Applications — 11 States, 1998–2006 Soo-Jeong Lee 1 

## , Louise Mehler 2 

## , John Beckman 3 

## , Brienne Diebolt-Brown 4 

## , Joanne Prado 5



## , Michelle Lackovic 6 

## , Justin Waltz 7 

## , Prakash Mulay 8 

## , Abby Schwartz 9 

## , Yvette Mitchell 10



## ,

Stephanie Moraga-McHaley 11 

## , Rita Gergely 12 

## , Geoffrey M Calvert 1

1 

## Division of Surveillance, Hazard Evaluations, and Field Studies, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Ci ncinnati, Ohio

2 

## California Environmental Protection Agency, Sacramento, California

3 

## Public Health Institute, Oakland, California

4 

## Texas Department of State Health Services, Austin, Texas

5 

## Washington State Department of Health, Olympia, Washington

6 

## Louisiana Department of Health and Hospitals, New Orleans, Louisiana

7 

## Oregon Health Authority, Portland, Oregon

8 

## Florida Department of Health, Tallahassee, Florida

9 

## Michigan Department of Community Health, Lansing, Michigan

10 

## New York State Department of Health, Troy, New York

11 

## New Mexico Department of Health, Albuquerque, New Mexico

12 

## Iowa Department of Public Health, Des Moines, Iowa

Corresponding author: Geoffrey Calvert, MD, MPH NIOSH

4676 Columbia Parkway, R-17 Cincinnati, OH 45226 Phone: 513-841-4448 E-mail: jac6@cdc.gov Page 1 of 32

## 2

Running Title: Illnesses Associated with Agricultural Pesticide Drift Key Words: Agriculture, drift, pesticides, poisoning, surveillance Acknowledgements : Funding support was provided by NIOSH, EPA, and the state agencies that contributed data. The authors thank Walter Alarcon, Sangwoo Tak and Jia Li for assist ance in conducting this study and Marie Sweeney, Michael O’Malley, Jennifer Sass, Misty Hein, and EPA for providing comments to improve this manuscript.

Conflict of interest: The authors have no conflicts of interest to declare. Mr. Beckman is assigned to the California Department of Public Health by his employer (Publi c Health Institute [PHI]), and has never been involved in any advocacy activities of PHI.

Disclaimer : The findings and conclusions in this report are those of the authors and do not necessarily represent the views of NIOSH or each author’s state agency

.

Abbreviations:

CDC Centers for Disease Control and Prevention CDPR California Department of Pesticide Regulation CI Confidence Interval CIC Census Industry Codes EPA U.S. Environmental Protection Agency FIFRA Federal Insecticide, Fungicide, and Rodenticide Act NIOSH National Institute for Occupational Safety and Health OR Odds Ratio PISP Pesticide Illness Surveillance Program SENSOR Sentinel Event Notification System for Occupational Risks Page 2 of 32

## 3

Abstract Background: Pesticides are widely used in agriculture and off-target pesticide dri ft results in exposures to workers and the public. Objective : Estimate the incidence of acute illnesses from pesticide drift from outdoor agricultural applications, and describe drift expos ure and illness

characteristics. Methods: Data were obtained from the National Institute for Occupational Safety and Health’s Sentinel Event Notification System for Occupational Risks-Pe sticides Program and the California Department of Pesticide Regulation. Drift included off-ta rget movement of pesticide spray, volatiles, and contaminated dust. Acute illness cases were characterized by demographics, pesticide and application variables, health effects, and contributing factors.

Results: During 1998–2006, 2,945 cases associated with agricultural pesticide drift were identified from 11 states. Forty-seven percent had exposures at work, 92% experie nced low severity illness, and 14% were children (<15 years). The annual incidence ranged fr om 1.39 to 5.32 per million persons over the 9-year period. The overall incidence (in million person-y ears) was 114.3 for agricultural workers, 0.79 for other workers, 1.56 for nonoccupational cases, and 42.2 for residents in 5 agriculture-intensive counties in California. Soil applications with fumigants were responsible for the largest proportion (45%) of cases. Aerial appli cations accounted for 24% of cases. Common factors contributing to drift cases included weathe r conditions, improper seal of the fumigation site, and applicator carelessness near non -target

areas. Conclusions: Agricultural workers and residents in agricultural regions were found to have the highest rate of pesticide poisoning from drift exposure, and soil fumigations w ere a major hazard causing large drift incidents. These findings highlight areas where interventions to reduce off-target drift could be focused. Page 3 of 32

## 4

Introduction Pesticide drift, which is the off-target movement of pesticides, is recogni zed as a major cause of pesticide exposure affecting people as well as wildlife and the envir onment. In the United States in 2004, more than 1,700 investigations were conducted in 40 states due to drift complaints and 71% of the incidents confirmed that drift arose from pesticide applic ations to agricultural crops (Association of American Pesticide Control Officials, 20 05). Pesticide drift has been reported to account for 37-68% of pesticide illnesses among U.S. agricultural workers (California Department of Pesticide Regulation [CDPR] 2008; Calvert et al. 2008). Community residents, particularly in agricultural areas, are also at risk of exposur e to pesticide drift from nearby fields. Agricultural pesticides are often detected in rural homes (H arnly et al. 2009; Quandt et al. 2004). Alarcon et al. (2005) reported that 31% of acute pesticide illnesses t hat occurred at U.S. schools were attributed to drift exposure. The occurrence and extent of pesticide drift is affected by many factors such as the nature of the pesticide (e.g., fumigants are highly volatile, increasing their prope nsity for off-site movement [U.S. Environmental Protection Agency (EPA), 2010]), equipment and application techniques (e.g., size and height of the spray nozzles), the amount of pesticides appli ed, weather (e.g., wind speed, temperature inversion), and operator care (Hofman and Solseng 2001). Pesticide applicators are required to use necessary preventive measures and comply with label requirements to minimize pesticide drift. Pesticide regulations such as th e Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Worker Protection Standard, an amendme nt to FIFRA, require safety measures for minimizing the risk of pesticide ex posure, and many states have additional regulations for drift mitigation (Feitshans 1999). Better understanding about the magnitude, trend, and characteristics of pestic ide Page 4 of 32

## 5

poisoning from drift exposure of agricultural pesticides would assist regulatory authorities with regulatory, enforcement, and education efforts. The purpose of this study was to est imate the magnitude and incidence of acute pesticide poisoning associated with pesticide dri ft from outdoor agricultural applications in the U.S. during 1998–2006 and describe the exposure and illness characteristics of pesticide poisoning cases arising from off-t arget drift. Factors associated with illness severity and large events were also examined.

Materials and Methods Data on acute pesticide poisoning cases were obtained from the National Instit ute for Occupational Safety and Health (NIOSH)’s Sentinel Event Notification Sy stem for Occupational Risks (SENSOR)-Pesticides program and CDPR’s Pesticide Illness S urveillance Program (PISP). The SENSOR-Pesticides program has collected pesticide poisoning surve illance data from 12 states, using standardized definitions and variables available since 1998 (C alvert et al. 2010). This study included data from 11 states for the following years: Arizona (1998–2000), California (1998–2006), Florida (1998–2006), Iowa (2006), Louisiana (2000–2006), Michigan (2000–2006), New Mexico (2005–2006), New York (1998–2006), Oregon (1998–2006), Texas (1998–2006), and Washington (2001–2006). North Carolina, which joined SENSOR-Pesticides in 2007, was not included. Because each state removes personal identifiers from the data prior to submission to the Centers for Disease Control and Prevention (CDC), this study was exempt from consideration by the federal Human Subjects Review Board. Participating surveillance programs identify cases from multiple source s including health care providers, poison control centers, workers’ compensation claims, and state or local government agencies. They collect information on the pesticide exposure incide nt through investigation, interview, and/or medical record review. On some occasions such as large drift Page 5 of 32

## 6

events, active surveillance is undertaken for further case finding by intervi ewing individuals living or working within the vicinity affected by the off-target drift (Bar ry et al. 2010). Although SENSOR-Pesticides focuses primarily on occupational pesticide poisoning s urveillance, all of the SENSOR-Pesticides state programs except California collect dat a on both occupational and nonoccupational cases. In California, PISP captures both occupational and nonoccupational cases. SENSOR-Pesticides and PISP classify cases based on the streng th of evidence for pesticide exposure, health effects, and the known toxicology of the pesticide, and use sli ghtly different criteria for case classification categories (Calver t et al. 2010). This study restricted the analyses to cases classified as definite , probable , possible , or suspicious by SENSOR-Pesticides

and definite , probable , or possible by PISP. Analyses restricted to definite and probable cases only were also performed. Because these findings were similar to those that included all four classification categories (i.e., definite , probable , possible , or suspicious ), only the findings that used the four classification categories were reported. In this study, a drift case was defined as acute health effects in a person exposed to pesticide drift from an outdoor agricultural application. Drift exposure included any of the following pesticide exposures outside their intended area of application: 1) spra y, mist, fumes, or odor during application; 2) volatilization, odor from a previously treated field, or mig ration of contaminated dust; and 3) residue left by offsite movement. It should be noted that our dr ift definition is broader than EPA’s “spray or dust drift” definition, which excludes post- application drift caused by erosion, migration, volatility, or windblown soil particles (EP A 2001). A drift

event was defined as an incident where one or more drift cases experienced drift ex posure from a particular source. Both occupational and nonoccupational cases were included. An occupational

case was defined as an individual exposed while at work. Among occupational cases, Page 6 of 32

## 7

agricultural workers were identified using 1990 and 2002 Census Industry Codes (CIC): (1990 CIC = 010, 011, 030; 2002 CIC = 0170, 0180, 0290) (U.S. Census Bureau 1992, 2005). The process of case selection is presented in Figure 1. We selected cases if exposed to pesticides applied for agricultural use including farm, nursery, or animal produc tion, and excluded cases exposed by ingestion, direct spray, spill, or other direct exposure . We then manually reviewed all case reports and excluded persons exposed to pesticides used f or indoor applications (e.g., greenhouses, produce packing facilities), persons exposed wi thin a treated area (e.g., pesticide applicators exposed by pesticides blown back by wind, workers wor king within or passing through the field being treated), and persons exposed to pesticides being mi xed, loaded, or transported. Drift cases therefore represented the remaining 9% and 27% of all pesticide illness cases identified by the SENSOR-Pesticides and PISP, r espectively. We also searched for duplicates from the two programs identifying California cases . Since personal identifiers were unavailable, date of exposure, age, sex, active ingredients, and count y were used for comparison. A total of 60 events and 171 cases were identified by both California prog rams. These were counted only once and were included in the PISP total only. Drift events and cases were analyzed by the following variables: state , year and month of exposure, age, gender, location of exposure, health effects, illness severity, pe sticide functional/chemical class, active ingredient, target of application, appli cation equipment, detection of violations, and factors contributing to the drift incident. EPA toxicity c ategories ranging from toxicity I (the most toxic) to IV (the least toxic) wer e assigned to each product (EPA 2007). Cases exposed to multiple products were assigned to the toxicity categ ory of the most toxic pesticide they were exposed to. Illness severity was cate gorized into low, moderate,

and high using criteria developed by the SENSOR-Pesticides program (Calvert et a l. 2010). Low Page 7 of 32

## 8

severity refers to mild illnesses that generally resolve without treatment. Moderate severity refers to illnesses that are usually systemic and require medical treatment. High severity refers to lifethreatening or serious health effects that may result in permanent impairm ent or disability. Contributing factors were retrospectively coded with available narrative de scriptions. One NIOSH researcher (SJL) initially coded contributing factors for all c ases. Next, for SENSORPesticides cases, state health department staff reviewed the codes and e dited as necessary. Any discrepancies were resolved by a second NIOSH researcher (GMC). For PISP cases, relatively detailed narrative descriptions were available for all incidents. These na rratives summarize investigation reports provided by county agriculture commissioners, who invest igate all suspected pesticide poisoning cases reported in their county. After initial co ding, two NIOSH researchers discussed those narratives that lacked clarity to reach cons ensus. Data Analysis Data analysis was performed with SAS v 9.1. Descriptive statistics were us ed to

characterize drift events and cases. Incidence rates were calcula ted by geographic region, year, sex, and age group. The numerator represented the total number of respective cases i n 1998– 2006. Denominators were generated using the Current Population Survey microdata files for the relevant years (U.S. Census Bureau 2009). For total and nonoccupational rates, the denomina tors were calculated by summing the annual average population estimates. A nonoccupat ional rate for agriculture-intensive areas was calculated by selecting the five counti es in California where the largest amount of pesticides were applied in 2008 (Fresno, Kern, Madera, Monterey, and Tul are) (CDPR 2010). For occupational rates, the denominators were calculated by summing t he annual employment estimates including both “employed at work” and “employed but abse nt.” The denominator for agricultural workers was obtained using the same 1990/2002 CIC codes used t o Page 8 of 32

## 9

define agricultural worker cases (U.S. Census Bureau 1992, 2005). Moreover, in California where data on pesticide usage are available, incidence was calculated per n umber of agricultural applications and amount of pesticide active ingredient applied (CDPR 2009). Incidence trend over time was examined by fitting a Poisson regression model of rate on year and deriving the regression coefficient and its 95% confidence intervals (CIs). Drift events were dichotomized by the size of events into small events involving < 5

cases and large events involving ≥ 5 cases. This cut point was based on one of the criteria used by CDPR to prioritize event investigations (CDPR 2001). Illness severity wa s dichotomized into

low and moderate/high . Simple and multivariable logistic regressions were performed. Odds ratios (OR) and 95% CIs were calculated.

Results Number and Incidence of Drift Events and Cases From 1998 through 2006, we identified 643 events and 2,945 illness cases associated with pesticide drift from agricultural applications (Figure 1). Of these, 382 e vents (59%) and 791 cases (27%) were identified by SENSOR-Pesticides (excluding 60 events an d 171 cases also identified by PISP), and 261 events (41%) and 2,154 cases (73%) were identified by PI SP. Drift cases consisted of 53 definite (1.8%), 2,019 probable (68.6%), 823 possible (27.9%), and 50 suspicious (1.7%) cases. Among drift cases, 1,565 (53%) were nonoccupational and 1,380 (47%) were occupational. Agricultural workers accounted for 73% (n=1,010) of the occupational c ases. A total of 340 events (53%) occurred between May and August and these involved 1,407 cases (48%). The overall incidence rate of drift-related pesticide poisoning was 2.93/milli on personyears (Table 1). The rates of nonoccupational and occupational drift-related pest icide poisoning Page 9 of 32

## 10

were 1.56 and 2.89, respectively. Among occupational cases, the rate was 114.3 for agric ultural workers and 0.79 for all other workers. Among nonoccupational cases identified in Calif ornia, the rate was 42.2 for residents in the 5 agriculture-intensive counties and 0.61 for reside nts of all other California counties (data not shown). The rate was highest in the western st ates for both nonoccupational and occupational cases (Table 1). In California, per 100,000 agricultural applications, 1.6 drift events and 11.8 cases were identified; per 10 million pounds applied, 1.9 events and 14.4 cases were identified (data not shown). The total annual incidence rate ranged from 1.39 to 5.32 per million persons over the 9- year time period (Table 1). Over time, the rate of drift cases involved in large e vents showed the same pattern as the rate of all drift cases, showing a spike every three y ears (Figure 2). The rate of drift cases involved in small events varied within a narrow range from 0.49 to 1.11 and there was no significant rate change over this time period; however, for the 5 states tha t provided data for all 9 years, a significant decrease in the rate was found (i.e., an estimat ed 9% decrease per year, 95% CI 3–15%, p = 0.004). Men comprised 53% of all cases (Table 1). The rate by gender was similar am ong nonoccupational cases. For occupational cases, the rate was 1.25 times higher in male workers than female workers, but 2.89 times higher in female agricultural workers than ma le agricultural workers. Among nonoccupational cases, children aged < 15 years accounted for 33% of ca ses with known age and showed the highest rate (1.88/million person-years) (Table 1). Responsible Pesticides, Application Targets, and Application Equipment In 430 (67%) of 643 drift events, exposure was to pesticides from a single functional class (Table 2). Insecticides were the most commonly identified (31% of event s), accounting for 23% (n=678) of all cases. Fumigants were involved in only 8% of drift events but accounted for Page 10 of 32

## 11

45% (n=1,330) of all cases. Organophosphorous compounds were the most common pesticide chemical class involved in drift events (28%). Most cases (66%) were exposed to toxi city I (high toxicity) pesticides. For the intended application targets, 71% of events involved applications to fruit, grain/fiber/grass, or vegetable crops (Table 2). Soil applications accounted for 9% of drift events and 45% of all cases. For application equipment, aerial applications (e.g., by airpl ane) were responsible for 39% of drift events, accounting for 24% of all cases. Chemigation (i.e., application via an irrigation system) or soil injectors were used in 7% of drift events and accounted for 44% of cases. All soil injector events and 95% of chemigation events involved t he use of fumigants applied to soil (data not shown). Location of Exposure and Health Effects Common exposure locations were private residences (44%) and farms/nurseries ( 37%) (Table 3). More than half of cases experienced ocular (58%) or neurological ( 53%) symptoms/signs and illness severity was low for most cases (92%) (Table 3) . Moderate/high severity illness was significantly associated with female sex, olde r age groups, and exposure to multiple active ingredients, before and after controlling for other case and p esticide characteristics (p < 0.05) (Table 4). Compared to fumigants, exposures to herbicide s, insecticides, or multiple classes were significantly associated with m oderate/high severity illness. Table 5 provides the list of 15 active ingredients most commonly found among drift case s and their distribution according to illness severity. Size of Drift Events Most drift events involved a single case (n=387, 60%). For multi-person events, 168 events (26% of the total) involved 2–4 cases, 78 events (12%) involved 5–29 cases, and 10 Page 11 of 32

## 12

events (1.5%) involved ≥ 30 cases. Table 6 provides details on the 10 largest events. Detailed investigation reports of some of these events are available elsewhere (B arry et al. 2010; CDC 2004; O'Malley et al. 2005). The occurrence of large versus small events (events with ≥ 5 cases compared with <5 cases) was significantly associated with the use of fumi gants (compared to insecticides), and applications to soil, small fruit crops, or leafy vegetable crops (compared to other targets) (p < 0.05) (Table 7). Contributing Factors to Drift Incidents Of 299 drift events with information on violations of pesticide regulations, 220 (74%) had one or more violations and accounted for 2,093 cases (89% of cases with violation information) (Table 8). However, not all of the observed violations may have directly contributed to the drift exposure. Factors contributing to the drift exposure were ident ified in 164 events accounting for 1,544 (52%) cases. Common contributing factors identified for drift events included applicators’ carelessness near/over non-target sites (e.g., fl ew over a house, did not turn off a nozzle at the end of the row), unfavorable weather conditions (e.g., high wind speed, temperature inversion), and poor communication between applicators/growers and other s. Improper seal of the fumigation site (e.g., tarp tear, early removal of seal ), identified in 9 events, accounted for the largest proportion (60%) of cases with contributing factors ident ified. The distance between the application and exposure site was identified in 1,428 (48%) cases (Table 8). Occupational cases accounted for 68% of cases exposed within 0.25 mi les of the application site, and nonoccupational cases accounted for 73% of cases exposed over 0.25 mile s

away.

Discussion To our knowledge, this is the first comprehensive report of drift-related pestic ide Page 12 of 32

## 13

poisoning in the US. We identified 643 events involving 2,945 illness cases associated with pesticide drift from outdoor agricultural applications during 1998–2006. Pesticide drift included pesticide spray, mist, fume, contaminated dust, volatiles and odor that moved away fr om the application site during or after the application. While the incidence for cases involved in small drift events (<5 cases) tended to decrease over time, the overall incidence ma intained a consistent pattern chiefly driven by large drift events. Large drift events were commonly associated with soil fumigations. Occupational Exposure Occupational pesticide poisoning is estimated at 12–21/million U.S. workers per y ear (Calvert et al. 2004; Council of State and Territorial Epidemiologists n.d.). Compar ed to those estimates, our estimated incidence of 2.89/million worker-years suggests that 14–24% of occupational pesticide poisoning may be attributed to off-target drift from agri cultural applications. It should be noted that our study included pesticide drift from outdoor applicati ons only and excluded workers exposed within the application area. Our findings show that the r isk of illness resulting from drift exposure is largely borne by agricultural w orkers, and the incidence (114.3/million worker-years) was 145 times greater than that for all other workers . Current regulations require agricultural employers to protect workers from exposur e to agricultural pesticides, and pesticide product labels instruct applicators to avoid contacting hum ans directly or through drift (EPA 2009). Our study found that the incidence of drift-related pesticide poisoning was highe r among female and younger agricultural workers and in western states. These groups were previously found to have a higher incidence of pesticide poisoning (Calvert et al. 2008). It is not known wh y the incidence is higher among female and younger agricultural workers, but hypothe ses include Page 13 of 32

## 14

that these groups are at greater risk of exposure, that they are more susceptibl e to pesticide toxicity, or that they are more likely to report exposure/illness or seek medi cal attention. However, consistent patterns were not observed among workers in other occupations, requi ring further research to identify the explanation. The higher incidence in the wester n states may suggest that workers in this region are at higher risk of drift exposure; howeve r, it may also have resulted from better case identification in California and Washington states through their higherstaffed surveillance programs, extensive utilization of workers’ compens ation reports in these states, and use of active surveillance for some large drift events in Californi a. Nonoccupational Exposure This study found that more than half of drift-related pesticide poisoning cases re sulted from nonoccupational exposures and 61% of those were exposed to fumigants. California data suggest that residents in agriculture-intensive regions have a 69 times higher r isk of pesticide poisoning from drift exposure compared to other regions. This may reflect Califor nia’s use of active surveillance for some large drift events. Children were found to have the g reatest risk among nonoccupational cases. The reasons are not known but may be because children have higher pesticide exposures, greater susceptibility to pesticide toxicity or greater medical attention seeking by concerned parents. Recently several organizations submitted a peti tion to the U.S. EPA asking the agency to evaluate children’s exposure to pesticide drift and adopt interim prohibitions on the use of drift-prone pesticides near homes, schools, and parks (Goldman et a l. 2009). Contributing Factors Soil fumigation was a major cause of large drift events, accounting for the l argest proportion of cases. Due to the high volatility of fumigants, specific measures ar e required to Page 14 of 32

## 15

prevent emissions after completion of the application. Given the unique drift risks posed by fumigants, EPA regulates the drift of fumigants separately from non-fumigant pesticides. EPA recently adopted new safety requirements for soil fumigants which took effect i n early 2011, and include comprehensive measures designed to reduce the potential for direct fum igant exposures, reduce fumigant emissions, improve planning, training, and communications, and promote early detection and appropriate responses to possible future incidents (EPA 2010). Requirements for buffer zones are also strengthened. For example, fumigants that generally r equire a > 300 foot buffer zone are prohibited within 0.25 miles (1,320 feet) of “difficult-to-evacuate” s ites (e.g., schools, daycare centers, hospitals). We found that, of 738 fumigant-related cases wi th information on distance, 606 (82%) occurred > 0.25 miles from the application site, which suggests that the new buffer zone requirements, independent of other measures to increa se safety, may not be sufficient to prevent drift exposure. This study also showed the need to reinforce compliance with weather-related requirements and drift monitoring activities. Moreover, applicators should be aler t and careful, especially when close to non-target areas such as adjacent fields, houses, a nd roads. Applicator carelessness contributed to 79 events (48% of 164 events where contributing factors wer e identified), of which 56 events involved aerial applicators. Aerial applicatio n was the most frequent application method found in drift events, accounting for 249 events (39%). Drift hazards from aerial applications have been well documented (CDC 2008; Weppner et al. 2006). Applicators should use all available drift management measures and equipment to re duce drift exposure, including new validated drift reduction technologies as they become ava ilable.

Limitations This study requires cautious interpretation especially for variables with m issing data on Page 15 of 32

## 16

many cases (e.g., age, violation, contributing factors, distance). This study als o has several limitations. First, our findings likely underestimate the actual magnitude o f drift events and cases because case identification principally relies on passive surveillance s ystems. Such underreporting might have allowed the totals to be appreciably influenced by a handful of California episodes in which active case-finding located relatively large numbers of aff ected people. Pesticide-related illnesses are underreported due to individuals not seeking medic al attention (because of limited access to health care or mild illness), misdiagnosis, and he alth care provider failure to report cases to public health authorities (Calvert et al. 2008). Data f rom the National Agricultural Workers Survey suggests that the pesticide poisoning rates for agri cultural workers may be an order of magnitude higher than those identified by the SENSOR-Pes ticides and PISP programs (Calvert et al. 2008). Second, the incidence of drift cases from agricult ural applications may have been underestimated by using crude denominators of total populat ion and employment estimates which may also include those who are not at risk. On the othe r hand, the incidence for agricultural workers may have been overestimated if the deno minator data undercounted undocumented workers. Third, the data may include false-positive cases bec ause clinical findings of pesticide poisoning are nonspecific and diagnostic tests ar e not available or rarely performed. Fourth, when data from SENSOR-Pesticides and PISP were c ombined, some duplication of cases and misclassification of variables may have occurred al though steps were taken to identify and resolve discrepancies. Also there may be differences i n case detection sensitivity between SENSOR-Pesticides and PISP since the two programs use slightly different case definitions. Lastly, contributing factor information was not available for 48% of cases, either because an in-depth investigation did not occur, or sufficiently detailed findings were not entered into the database. The retrospective coding of contributing factors was oft en based on Page 16 of 32

## 17

limited data and may have produced some misclassification.

Conclusion The study findings suggest that the incidence of acute illness from off-targ et pesticide drift exposure was relatively low during 1998–2006 and most cases presented with low-se verity illness. However, the rate of poisoning from pesticide drift was 69 times higher for residents in 5 agriculture-intensive California counties compared with other counties, and the rate of occupationally exposed cases was145 times greater in agricultural workers t han in nonagricultural workers. These poisonings may largely be preventable through prope r prevention measures and compliance with pesticide regulations. Aerial applications wer e the most frequent method associated with drift events, and soil fumigations were a major cause of large drift events. These findings highlight areas where interventions to reduce pesticide dr ift could be

focused. Page 17 of 32

## 18

References Alarcon WA, Calvert GM, Blondell JM, Mehler LN, Sievert J, Propeck M, et al. 2005. Acute illnesses associated with pesticide exposure at schools. JAMA 294(4):455-465.

Association of American Pesticide Control Officials. 2005. Pesticide drift enforcement survey report. Available: http://aapco.ceris.purdue.edu/doc/surveys/DriftEnforce05R pt.html [accessed 16 June 2010]. Barry T, Oriel M, Verder-Carlos M, Mehler L, Edmiston S, O’Malley M. 2010. Com munity exposure following a drip-application of chloropicrin. Journal of Agromedicine 5:1-14. California Department of Pesticide Regulation. 2001. Pesticide/wildlife inc ident response plan training workbook. Available: http://www.cdpr.ca.gov/docs/county/training/pstwld/pstwldwb.pdf [accessed 16 May 2011]. California Department of Pesticide Regulation. 2008. Summary of results from t he California Pesticide Illness Surveillance Program 2006. Available: http://www.cdpr.ca.gov/docs/whs/pdf/hs1872.pdf [accessed 17 December 2009]. California Department of Pesticide Regulation. 2009. Pesticide use reporting. A vailable: http://www.cdpr.ca.gov/docs/pur/purmain.htm [accessed 15 June 2010]. California Department of Pesticide Regulation. 2010. DPR reports pesticide use declined again in 2008. Available: http://www.cdpr.ca.gov/docs/pressrls/2010/100107.htm Calvert GM, Karnik J, Mehler L, Beckman J, Morrissey B, Sievert J, et al. 2008. Acut e pesticide poisoning among agricultural workers in the United States, 1998-2005. Am J Ind Med 51(12):883-898. Calvert GM, Mehler LN, Alsop J, De Vries AL, Besbelli N. 2010. Surveillance of pes ticidePage 18 of 32

## 19

related illness and injury in humans. In: Hayes’ handbook of pesticide toxicology (Krieger RI, ed). 3rd ed. New York: Elsevier, 1313-1369. Calvert GM, Plate DK, Das R, Rosales R, Shafey O, Thomsen C, et al. 2004. Acute occupati onal pesticide-related illness in the US, 1998-1999: surveillance findings from the SENS ORpesticides program. Am J Ind Med 45(1):14-23. Centers for Disease Control and Prevention. 2004. Brief Report: Illness Associat ed with Drift of Chloropicrin Soil Fumigant into a Residential Area --- Kern County, California , 2003. MMWR 53(32):740-742. Centers for Disease Control and Prevention. 2008. Acute pesticide poisoning associat ed with pyraclostrobin fungicide--Iowa, 2007. MMWR 56(51-52):1343-1345. Council of State and Territorial Epidemiologists. n.d. Introduction and Guide to the Dat a Tables for Occupational Health Indicators. Available: http://www.cste.org/dnn/ProgramsandActivities/OccupationalHealth/Occ upationalHealth Indicators/tabid/85/Default.aspx [accessed 1December 2009]. Feitshans TA. 1999. An analysis of state pesticide drift laws. San Joaquin Agric L Rev 9:37:37-

93. Goldman P, Brimmer JK, Ruiz V. 2009. Pesticides in the air- Kids at risk: Petition t o EPA to protect children from pesticide drift. Available: http://earthjustice.org/sites/default/files/library/legal_docs /petition-pesticides-in-the-airkids-at-risk.pdf [accessed 17 May 2011]. Harnly ME, Bradman A, Nishioka M, McKone TE, Smith D, McLaughlin R, et al. 2009. Pesticides in dust from homes in an agricultural area. Environ Sci Technol 43(23):8767-

8774. Page 19 of 32

## 20

Hofman V, Solseng E. 2001. Reducing spray drift. Available: http://www.ag.ndsu.edu/pubs/ageng/machine/ae1210w.htm [accessed 16 December 2009]. O'Malley M, Barry T, Ibarra M, Verder-Carlos M, Mehler L. 2005. Illness es related to shank application of metam-sodium, Arvin, California, July 2002. J Agromedicine 10(4):27-42. Quandt SA, Arcury TA, Rao P, Snively BM, Camann DE, Doran AM, et al. 2004. Agricultural and residential pesticides in wipe samples from farmworker family resi dences in North Carolina and Virginia. Environ Health Perspect 112(3):382-387. U.S. Census Bureau. 1992. 1990 census of population and housing. Alphabetical index of industries and occupations, Washington, DC: US Department of Commerce. U.S. Census Bureau. 2005. Industry and Occupation 2002. Washington, DC; United States

Census Bureau. Available: http://www.census.gov/hhes/www/ioindex/ioindex02/view02.html [accessed 30 November 2008]. U.S. Census Bureau. 2009. Current Population Survey. Available: http://www.bls.census.gov/cps_ftp.html [accessed 28 October 2010]. U.S. Environmental Protection Agency. 2001. Pesticide registraion (PR) notice 2001-X dr aft: Spray and dust drfit lable statements for pesticide products. Available: http://www.epa.gov/PR_Notices/prdraft-spraydrift801.htm [accessed 30 Novembe r 2009]. U.S. Environmental Protection Agency. 2007. Label review manual - Precautionary sta tements Available: http://www.epa.gov/oppfead1/labeling/lrm/2007-lrm-chap-07.pdf [ac cessed 30 November 2009]. Page 20 of 32

## 21

U.S. Environmental Protection Agency. 2009. Pesticides: Health and safety - Worker sa fety and training. Available: http://www.epa.gov/opp00001/health/worker.htm [accessed November 30 2009]. U.S. Environmental Protection Agency. 2010. Implementation of risk mitigation measure s for soil fumigant pesticides. Available:http://www.epa.gov/oppsrrd1/reregistration/soil_fumigants/ [a ccessed 1 November 2010] Weppner S, Elgethun K, Lu C, Hebert V, Yost MG, Fenske RA. 2006. The Washington aerial spray drift study: children's exposure to methamidophos in an agricultural communi ty following fixed-wing aircraft applications. J Expo Sci Environ Epidemiol 16(5): 387-396. Page 21 of 3222Table 1.Number and incidence rateaof off-target drift events and pesticide poisoningcases by year, region, sex, and age, 11 States, 1998-2006Drift CasesOccupational CasesDrift EventsAll CasesNonoccupationalCasesAg Worker CasesdOther Worker CasesTotalVariable Count %CountPopulationestimatebRateCountRatecCountEmploymentestimateb,dRateCountEmploymentestimatebRateRateTotal643 1002,945 1004.1 2.931,5651.561,010 8.83 114.33370 468.0 0.792.89Year of exposure(# of states included)1998 (6)60 9.3130 93.6 1.39460.4945 1.11 40.4639 43.2 0.901.901999 (6)82 12.8407 95.0 4.282732.8772 1.12 64.2262 44.1 1.412.972000 (8)64 10.0193 110.3 1.75760.6993 1.24 74.9424 51.8 0.462.212001 (8)88 13.7177 112.6 1.57980.8743 1.12 38.4736 52.5 0.691.472002 (8)81 12.6580 113.7 5.102712.38281 1.11 252.3328 52.2 0.545.802003 (8)75 11.7348 116.4 2.992652.2843 0.79 54.6440 53.7 0.741.522004 (8)47 7.3232 117.4 1.98430.37177 0.75 235.3312 54.7 0.223.412005 (9)70 10.9642 120.6 5.324093.39168 0.75 224.7765 56.8 1.144.052006 (10)76 11.8236 124.5 1.90840.6788 0.84 104.5364 59.1 1.082.54RegionWeste433 67.32,484 397.9 6.241,240 3.12933 4.44 210.20311 184.9 1.686.57Southf193 30.0426 365.6 1.17311 0.8559 3.25 18.1756 170.7 0.330.66East/Centralg17 2.635 240.6 0.1514 0.0618 1.15 15.683 112.5 0.030.18Sexn/a0.0Male1560 491.6 3.17742 1.51554 6.90 80.27264 251.6 1.053.16Female1360 512.5 2.65807 1.57448 1.93 231.90105 216.5 0.492.53Unknown25 ----16--8----1------Agen/a< 15418 221.2 1.894151.883----0------15–24398 142.0 2.801821.28182 1.44 126.3934 67.8 0.503.1225–34453 140.0 3.241401.00240 1.81 132.5373 106.8 0.682.8835–44458 156.7 2.921811.16187 2.08 89.8990 122.3 0.742.2345–54306 136.1 2.251721.2678 1.59 49.0056 104.6 0.541.2655–64164 90.9 1.801031.1337 1.10 33.6124 52.0 0.461.1565+92 117.2 0.78800.689 0.81 11.113 14.6 0.210.78Unknown656----292--274----90------a. Per 1,000,000 persons.b. Numbers (in million) were estimated using the Current Population Survey data. Participating years vary by state. Only years of participation were included.c. Denominators were population estimates.d. Cases and employment estimates of agricultural workers were defined with 1990/2002 Census IndustryCodes (010, 011, 030; 0170, 0180, 0290).e. Arizona, California, New Mexico, Oregon, Washingtonf. Florida, Louisiana, Texasg. Iowa, Michigan, New YorkPage 22 of 32

## 23

Table 2. Off-target drift events and pesticide poisoning ca ses by pesticide and application characteristics, 11 states, 1998-2006 Drift Cases Drift Events (n=643) Total

(n=2,945) Occupational

(n=1,380) Nonoccupational

(n=1,565) Variable N % N % % % Pesticide functional class Insecticide only 198 30.8 678 23.0 32.9 14.3 Herbicide only 108 16.8 195 6.6 4.0 8.9 Fungicide only 29 4.5 64 2.2 3.7 0.8 Fumigant only 52 8.1 1,330 45.2 27.0 61.2 Other, single 43 6.7 87 3.0 2.8 3.1 Multiple 207 32.2 585 19.9 29.4 11.4 Unknown 6 0.9 6 0.2 0.2 0.2 Common pesticide chemical class a Organophosphorous compound 181 28.1 660 22.4 36.7 9.8 Inorganic compound 87 13.5 231 7.8 11.1 5.0 Pyrethroid 52 8.1 207 7.0 9.6 4.7 Dithiocarbamates b 47 7.3 726 24.7 22.5 26.5 N-methyl carbamates 33 5.1 71 2.4 4.1 1.0 Chlorophenoxy compound 26 4.0 47 1.6 0.9 2.2 Triazines 11 1.7 34 1.2 1.1 1.2 Maximum toxicity category I 203 31.6 1,944 66.0 59.9 71.4 II 167 26.0 468 15.9 21.2 11.2 III 154 24.0 327 11.1 13.6 8.9 Unknown 119 18.5 206 7.0 5.2 8.6 Application target Fruit crops 189 29.4 588 20.0 27.6 13.2 Grain/fiber/grass crops 185 28.8 411 14.0 12.8 15 .0 Vegetable crops 85 13.2 374 12.7 22.9 3.7 Soil 55 8.6 1,337 45.4 27.5 61.2 Landscape/forest 32 5.0 64 2.2 2.8 1.7 Undesired plants 29 4.5 44 1.5 0.9 2.0 Other (e.g., misc. crops, seed, livestock farm) 27 4.2 66 2.2 2.0 2.5 Unknown 41 6.4 61 2.1 3.6 0.8 Application equipment Aerial applicator 249 38.7 695 23.6 32.0 16.2 Handheld or backpack sprayer 24 3.7 63 2.1 3.8 0. 6 Chemigation 22 3.4 752 25.5 16.4 33.5 Soil injector 20 3.1 558 18.9 10.0 26.8 Other ground applicator 254 39.5 747 25.4 32.6 19 .0 Multiple 8 1.2 41 1.4 0.2 2.4 Unknown 66 10.3 89 3.0 4.9 1.4 a. Categories with the largest numbers of cases. Ev ents/Cases can be exposed to multiple categories. b. Mostly from single products. 

### Page 23 of 32

## 24

Table 3. Location of exposure, health effects, and illness severity of drift cases (n=2,945) Variable % Location of exposure Private residence 44.5 Farm/Nursery 36.7 Road/Right-of-way 5.6 School 3.6 Agricultural processing facility 2.4 Other/Unknown 7.2 Health effect a Eye (e.g., pain/irritation/inflammation, lacrimatio n) 58.2 Neurological (e.g., headache, paresthesia, dizzines s) 52.8 Respiratory (e.g., dyspnea, respiratory tract pain /irritation, cough) 47.8 Gastrointestinal (e.g., vomiting, nausea, diarrhea, abdominal pain) 41.5 Skin (e.g., pruritus, pain/irritation, rash) 14.7 Cardiovascular (e.g., chest pain) 5.1 Other (e.g., fatigue, fever) 11.4 Illness severity Low 92.2 Moderate 7.3 High 0.5 a. Cases can be included in multiple categories. 

### Page 24 of 32

## 25

Table 4. Illness severity by case and pesticide characteris tics High/Moderate Severity (n=230) Low severity (n=2,715) High/Moderate severity (versus Low) Variable N % N % OR 95% CI aOR b 95% CI Sex a Female 126 54.8 1,234 45.5 1.43 (1.09,1.87) 1.53 (1.15,2.04) Male 104 45.2 1,456 53.6 Ref Ref Age < 15 16 7.0 402 14.8 Ref Ref 15-24 28 12.2 370 13.6 1.90 (1.01,3.57) 1.34 (0.68,2.62) 25-34 48 20.9 405 14.9 2.98 (1.66,5.33) 1.95 (1.02,3.71) 35-44 48 20.9 410 15.1 2.94 (1.64,5.27) 1.91 (1.02,3.58) 45-54 38 16.5 268 9.9 3.56 (1.95,6.52) 2.34 (1.24,4.41) 55-64 21 9.1 143 5.3 3.69 (1.87,7.27) 2.42 (1.20,4.91) 65+ 16 7.0 76 2.8 5.29 (2.54,11.03) 3.67 (1.72,7.86) Unknown 15 6.5 641 23.6 0.59 (0.29,1.20) 0.63 (0.30,1.33) Work-related Yes 126 54.8 1,254 46.2 1.41 (1.08,1.85) 0.99 (0.70,1.40) No/Unknown 104 45.2 1,461 53.8 Ref Ref No. of active ingredients One 90 39.1 1,719 63.3 Ref Ref More than one 140 60.9 996 36.7 2.72 (2.07,3.58) 1.42 (1.02,1.99) Pesticide functional class Fumigant 35 15.2 1,295 47.7 Ref Ref Herbicides 33 14.3 162 6.0 7.54 (4.56,12.46) 4.10 (2.34,7.19) Insecticide 79 34.3 599 22.1 4.88 (3.24,7.35) 3.34 (2.10,5.32) Fungicides 2 0.9 62 2.3 1.19 (0.28,5.08) 0.77 (0.18,3.37) Multiple 71 30.9 514 18.9 5.11 (3.37,7.76) 3.09 (1.85,5.16) Other/Unknown 10 4.3 83 3.1 4.46 (2.13,9.32) 2.82 (1.29,6.15) a. Excluded unknown cases. b. Adjusted for all other variables. 

### Page 25 of 32

## 26

Table 5. Fifteen most common active ingredients for drift c ases and percentage of high/moderate severity Cases exposed to single active ingredient Active ingredient Functional class Chemical class Cases a (N=2,945) Total

(n=1,809) % of High/Moderate

Severity (n=90) b Metam-sodium Fumigant Dithicarbamate 664 664 3 Chloropicrin Fumigant Trichloronitromethane 637 532 1 Chlorpyrifos Insecticide Organophosphate 240 49 10 Sulfur Insecticide/Fungicide Inorganic compound 147 32 25 Mancozeb Fungicide Dithicarbamate 144 4 0 Methamidophos Insecticide Organophosphate 133 0 0 Malathion Insecticide Organophosphate 122 96 11 Spinosad Insecticide Spinosyn 107 1 0 Methyl-bromide Fumigant Alkyl bromide 84 11 27 Dimethoate Insecticide Organophosphate 68 10 20 Cyfluthrin Insecticide Pyrethroid 59 2 0 Methomyl Insecticide N-methyl carbamate 56 13 15 Atrazine Herbicide Triazine 54 8 0 lambda-Cyhalothrin Insecticide Pyrethroid 52 39 3 Propargite Acaricide/miticide Sulfite ester 52 10 3 0 a. Can be exposed to other active ingredients also. b. High (n=7), Moderate (n=83) 

### Page 26 of 3227Table 6.10 largest drift events, 1998-2006CasesPesticide applicationState YearTotal(n=1,293)Occupational(n=452)Non-occupational(n=841)Target Equipment Active ingredientCalifornia 1999 170 6 164Soil Chemigation Metam-sodiumCalifornia 2000 33 33 0Almonds Aerial application Chlorpyrifos, propargiteCalifornia 2002 250 72 178Soil Soil injector Metam-sodiumCalifornia 2002 123 123 0Soil Chemigation Metam-sodiumCalifornia 2003 161 10 151Soil Soil injector ChloropicrinCalifornia 2004 122 122 0Potatoes Aerial application MethamidophosCalifornia 2005 324 1 323Soil Chemigation ChloropicrinCalifornia 2005 42 42 0Soil Chemigation Metam-sodiumCalifornia 2005 34 34 0Oranges Ground sprayer Cyfluthrin, spinosadTexas 2005 34 9 25Cotton Ground sprayer Lambda-cyhalothrinPage 27 of 3228Table 7.Factors associated with large drift events (≥5 cases)Small Event (n=555) Large Event (n=88)Large Event(versus Small)N % N % OR (95% CI)Pesticide functional classInsecticide 172 31.0 26 29.5 RefFumigant29 5.2 23 26.1 5.25 (2.64,10.41)Multiple combination 178 32.1 29 33.0 1.08 (0.61,1.91)Other single pesticide class or unknown 176 31.7 1011.4 0.38 (0.18,0.80)Application targetSoil31 5.6 24 27.3 8.50 (4.57,15.79)Small fruit cropsa38 6.8 14 15.9 4.04 (2.03,8.06)Leafy vegetable cropsb25 4.5 8 9.1 3.51 (1.49,8.27)Otherc461 83.1 42 47.7 RefApplication methodAerial application 223 40.2 26 29.5 0.91 (0.54,1.53)Chemigation 20 3.6 22 25.0 8.58 (4.31,17.09)Otherd312 56.2 40 45.5 Refa. e.g., berries, grapes, currant.b. e.g., beets, celery, broccoli, lettuce, spinachc. Includes tall fruit or other vegetable crops, other crop categories, landscape/forest, undesired plants, livestock farms, unknown.d. Includes other ground application equipment, multiple, and unknown.Page 28 of 32

## 29

Table 8. Violation in and contributing factors to occurrenc e of drift incidents/exposures Drift Cases Drift Events (n=643) Occupational (n=1,380) Nonoccupational (n=1,565) Variable N % N % N % Violation of federal/state pesticide regulation Yes 220 a 73.6 971 85.6 1122 93.2 No 79 26.4 164 14.4 82 6.8 Unknown/Pending 344 245 361 At least one contributing factor identified b 164 (100) 486 (100) 1,058 (100) Applicator carelessness near non-target sites c 79 (48.2) 49 (10.1) 98 (9.3) By aerial applicator 56 (34.1) 21 (4.3) 66 (6.2) Weather (wind, temperature inversion) 75 (45.7) 30 9 (63.6) 593 (56.0) Poor/ineffective communication 19 (11.6) 102 (21. 0) 11 (1.0) Improper seal of fumigation site d 9 (5.5) 94 (19.3) 837 (79.1) Inappropriate monitoring e 7 (4.3) 118 (24.3) 199 (18.8) Applicator not properly trained or supervised 5 (3. 0) 45 (9.3) 0 (0.0) Excessive application 4 (2.4) 20 (4.1) 6 (0.6) Use of inadequate equipment f 2 (1.2) 125 (25.7) 2 (0.2) Other g 8 (4.9) 28 (5.8) 206 (19.5) Distance from application site n/a 700 (100) 728 (100) ≤ 50 feet 66 (9.4) 54 (7.4) > 50–100 feet 77 (11.0) 29 (4.0) > 100–300 feet 113 (16.1) 69 (9.5) > 300 feet–0.25 mile 267 (38.1) 93 (12.8) > 0.25–0.5 mile 175 (25.0) 256 (35.2) > 0.5–1 mile h 0 (0.0) 116 (15.9) > 1 mile i 2 (0.3) 111 (15.2) Note: Percentages in parentheses were calculated on ly among cases with available data a. 159 (72%) were identified by the California Dep artment of Pesticide Regulation b. Cases can be included in multiple categories. c. e.g., the applicator didn't turn off a nozzle a t the end of the row, the crop duster flew overhead

. d. e.g., leakage from torn tarp, early removal of seal, use of contaminated water e. e.g., did not measure wind speed, did not monit or drift from the application site f. e.g., used longer spray boom than specified on the label, used sprinklers without required calibra tion device. g. e.g., treated additional rows without permissio n, permeable soil type, aerial application with ver y low height, building/vehicle ventilator system sucking outside air in h. Cases are from three events in California, Louis iana, and Washington. i. Cases are from two events in California. 

### Page 29 of 32

## 30

Figure 1 . Eligible pesticide drift events and cases, 11 States, 1 998-2006

Figure 2 . Incidence rate of pesticide poisoning associated with off -target drift exposure over time, 11 states, 1998-2006 Page 30 of 32

### Figure 1. Eligible pesticide drift events and cases , 11 States, 1998-2006 190x142mm (300 x 300 DPI) 

### Page 31 of 32

### Figure 2. Incidence rate of pesticide poisoning ass ociated with off-target drift exposure over time, 11 states, 1998-2006 50x13mm (300 x 300 DPI) 

### Page 32 of 32