AMERICAN JOURNAL OF INDUSTRIAL MEDICINE 53:188–193 (2010)

Commentary

Using Surveillance Data to Promote Occupational

Health and Safety Policies and Practice at the

State Level: A Case Study

Geoffrey M.Calvert, MD, MPH1 and Sheila A.Higgins, RN, MPH2

Background Following the investigation of a birth defects cluster involving migrant

farmworkers employed in North Carolina and Florida, it became clear that greater efforts

were needed to protect agricultural workers from pesticide exposure.

Methods Documentation is drawn from peer-reviewed published articles, government

reports and news accounts.

Results The birth defects cluster was identified and investigated by state and federal

pesticide poisoning surveillance system staff. Following the investigation, efforts were

initiated to highlight pesticides as an important public health issue needing more attention.

A series of subsequent events led to the creation and passage of important legislation

recently enacted in North Carolina. The legislation resulted in funding to promote various

activities to prevent harm from pesticides including strengthening surveillance, improving

the quality of pesticide compliance inspections, and increasing and improving pesticide

safety training. The legislation also broadened the coverage of anti-retaliation rules to

include agricultural workers, and increased recordkeeping requirements pertaining to

pesticide applications.

Conclusion The important and positive impacts that can occur through surveillance

activities are highlighted. As such, it is important to continue to support and improve

occupational illness and injury surveillance programs. Am. J. Ind. Med. 53:188–193

2010. Published 2009 Wiley-Liss, Inc.{

KEY WORDS: congenital abnormalities; farmworkers; insecticides; pesticides;

prevention and control; surveillance

INTRODUCTION

Legislation was recently enacted in North Carolina

that resulted in funding to strengthen pesticide-poisoning

surveillance, improve the quality of pesticide compliance

inspections, and increase and improve pesticide safety

training. The legislation also extended anti-retaliation rules

to cover agricultural workers, and increased recordkeeping

requirements pertaining to pesticide applications. This

article describes the events that led to the creation and

passage of this important legislation.

Published 2009 Wiley-Liss,Inc.

{

This article is a US Government work and, as such, isin

the public domain in the United States of America.

1

Division of Surveillance, Hazard Evaluations, and Field Studies, National Institute for

Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio 2

North Carolina Department of Health and Human Services, Raleigh, North Carolina

The findings and conclusions in thisreport are those of the authors and do not necessarily

represent the views of the Centers for Disease Control and Prevention, or the North Carolina

Department of Health and Human Services.

*Correspondence to: Geoffrey M. Calvert, National Institute for Occupational Safety &

Health, 4676 Columbia Parkway, R-17, Cincinnati, OH 45226. E-mail: jac6@cdc.gov

Accepted 5 April 2009

DOI10.1002/ajim.20707. Published online in Wiley InterScience

(www.interscience.wiley.com)
SENTINEL EVENT NOTIFICATION

SYSTEM FOR OCCUPATIONAL RISKS

(SENSOR)—PESTICIDES

This story begins with the Sentinel Event Notification

System for Occupational Risks (SENSOR) program. Were

it not for this program, the potential role of pesticides in

the birth defects cluster described in this article may not

have been discovered, and the cluster may have gained little

attention. The birth defects cluster was a sentinel health

event.

A sentinel health event is ‘‘a condition that can be used to

assess the stability or change in health levels of a population’’

[Last, 2001]. It has been argued that pesticide poisoning,

along with heavy metal poisoning, is a useful sentinel to

trigger action against environmental toxins [Pew Environmental Health Commission, 2001]. Recognizing the importance of sentinel health surveillance, the National Institute

for Occupational Safety and Health/Centers for Disease

Control and Prevention (NIOSH/CDC) supports such

surveillance activities by providing cooperative agreement

funding and technical support to state health departments

through the Sentinel Event Notification System for Occupational Risks (SENSOR) program. Since 1987, acute occupational pesticide-related illness and injury has been one of the

conditions under surveillance by SENSOR [Calvert et al.,

2004]. The SENSOR-pesticides program is also partially

funded by the US Environmental Protection Agency (EPA).

Health departments in seven states (California, Iowa,

Michigan, New York, North Carolina, Texas, and Washington State) are provided federal funding to bolster

pesticide-related illness and injury surveillance. Five additional states are unfunded SENSOR-Pesticides program

partners (Arizona, Louisiana, Florida, New Mexico, and

Oregon). Besides identifying, classifying, and tabulating

pesticide poisoning cases using a standardized case definition

and standardized variables, the states periodically perform

in-depth investigations of pesticide-related events, and

develop interventions aimed at particular industries or

pesticide hazards. State programs are notified about potential

pesticide poisoning cases most often from their state

workers’ compensation system, poison control centers, and

other state and local government agencies (e.g., state

department of agriculture, and local county health departments). Deidentified case data is submitted annually to

NIOSH by each SENSOR-Pesticides state program. NIOSH

aggregates this data to produce a national database consisting

of acute pesticide-related illness and injury cases. However,

the SENSOR-Pesticides program is most useful for timely

identification of emerging pesticide problems which typically manifest as acute pesticide poisoning (e.g., total release

foggers [CDC, 2008a], pesticide poisoning associated with

pesticide exposures at schools [Alarcon et al., 2005], and

pesticide poisoning associated with pyraclostrobin, a relatively new fungicide [CDC, 2008b]). Note that a birth defects

cluster had not been previously detected by the program.

NIOSH also supports and organizes workshops twice

per year that are attended by representatives from each state

that participates in the SENSOR-Pesticides program. The

purpose of these workshops is to discuss significant

pesticide-related topics, including emerging pesticide problems, and ways to increase the impact of the SENSORPesticides program at the state and federal level.

A BIRTH DEFECTS CLUSTER IN A

FARMWORKER POPULATION

One emerging problem identified by the SENSORPesticides program was a cluster of congenital anomalies

among three infants born to pesticide-exposed mothers

[Calvert et al., 2007]. In February 2005, the Healthy Start

program in the Collier County Health Department (CCHD)

in Florida identified three infants with congenital anomalies

who were born within 8 weeks of each other and determined

that all three mothers worked for the same tomato grower.

All three women worked on the grower’s Florida farms in

2004 before transferring to its North Carolina farms. CCHD

notified the Florida Department of Health (FLDOH) who

notified the Florida Department of Agriculture and Consumer Services (FLDACS) and these two state agencies

collaborated in investigating the cluster. US EPA Region 4

was notified about the cluster by FLDACS. In August 2005,

the North Carolina Division of Public Health (NCDPH) was

notified of these births by the North Carolina Department of

Agricultural and Consumer Services (NCDACS), who was

notified by EPA Region 4 in April 2005. The SENSORPesticides program at NIOSH was alerted in September 2005

and with the assistance of State health departments in Florida

and North Carolina collected case reports, and pesticide

exposure histories.

During the period of organogenesis (approximately days

14–59 after fertilization) when birth defects are most likely

to occur, all three mothers appear to have unknowingly

worked in tomato fields that were under a restricted

entry interval (REI) because the fields were recently treated

with pesticides, some of which have been shown to be

teratogenic when tested individually in animals [Florida

Department of Agriculture and Consumer Services, 2005].

According to the Worker Protection Standard (WPS) for

Agricultural Pesticides, which are a set of rules promulgated

by EPA aimed at reducing pesticide exposures among

agricultural workers (40 CFR 170), workers are prohibited

from entering a field when an REI is in effect, unless the

worker is provided appropriate personal protective equipment (PPE). There is no evidence that PPE was provided to

these mothers.

During the period of organogenesis, one case (case 1)

only worked on the grower’s North Carolina farms and two

Using Surveillance to Promote Occupational Health 189
cases (cases 2 and 3) only worked on the grower’s Florida

farms. Due to jurisdictional limits, state government staff

investigated only exposures that occurred in their own state.

As a result both states initially discounted the cluster because

neither state had data showing that all three mothers had

potential pesticide exposure during the period of organogenesis [Collier County Health Department, 2005; Florida

Department of Agriculture and Consumer Services, 2005].

During the January 2006 biannual workshop organized by

federal staff from the CDC/NIOSH SENSOR-Pesticides

program, staff from the CCHD and NCDPH presented their

respective findings on the cluster. Following these presentations, it became clear to all workshop attendees that all three

mothers had potential pesticide exposure during the period of

organogenesis. This information was shared with EPA, and

other public health partners. In addition, the SENSORPesticides program began work on a manuscript describing

the cluster, including specifics on the pesticide exposures

experienced by each mother, that was ultimately published in

Environmental Health Perspectives [Calvert et al., 2007].

DETAILS ON THE THREE CASES

Below is a brief description of each of the three birth

defect cases. Additional details can be found in Calvert et al.

[2007].

Case 1

This infant was born with tetra-amelia (absence of all

four limbs). The parents had no other known birth defect risk

factors. The period for limb development is 24–36 days after

fertilization [Moore and Persaud, 2003]. During this period,

this child’s mother appears to have unknowingly worked in

violation of the REI for up to 4 days involving exposure to

several pesticides, including mancozeb. Mancozeb and its

metabolite, ethylenethiourea (ETU), have been shown to

produce limb reduction defects, cleft palate, and brachygnathia following high oral doses given to rats [Larsson et al.,

1976].

Case 2

This infant was born with mild Pierre Robin syndrome

(micrognathia, high arched palate, and mild persistent

palatine rugae). The father of this child has micrognathia.

During gestational days (i.e., days after fertilization) 14–57,

this child’s mother appears to have unknowingly worked in

violation of the REI for up to 8 days. On seven of these days,

the pesticides applied to the fields where the mother worked

included methamidophos. In addition, on gestational days 7

and 10, the mother worked in fields when an REI was

potentially in effect (mancozeb on both days, and abamectin

and methylpyrrolidone on day 7). The mother has three other

living children, none of whom have birth defects. This

mother also had one previous stillbirth but without obvious

birth defects. We are unaware of animal evidence for an

association between the birth defects found in case 2 and

methamidophos, abamectin, or methylpyrrolidone exposure,

but there is evidence to suggest that these pesticides are

teratogens [Florida Department of Agriculture and Consumer Services, 2005]. On the other hand, mancozeb and its

metabolite ETU have been shown to produce abnormal

shortening of the mandible [Larsson et al., 1976; Stula and

Krauss, 1977].

Case 3

This infant had multiple severe malformations including

cleft lip and palate, imperforate anus, solitary kidney,

vertebral anomalies, dysplastic lowset ears, and ambiguous

genitalia. These findings are reminiscent of a severe type of

the Goldenhar Syndrome (also referred to as oculo-auriculovertebral sequence). Death occurred at three days of age.

During gestational days 14–59, the mother appears to have

unknowingly worked inviolation of the REI for up to 10 days.

On eight of these days, methamidophos was among the

pesticides applied to the fields where the mother appears

to have worked. The mother had two previous and one

subsequent pregnancy. One previous pregnancy occurred

3 years earlier and resulted in a malformed fetus and ended in

miscarriage. The mother worked for the same grower during

this pregnancy. During the other previous pregnancy and the

subsequent pregnancy the mother was not employed by the

grower, and these pregnancies resulted in normal children.

Methamidophos has been shown to be associated with anotia,

anencephaly, paddle-shaped limbs, and microopthalmia in

animals [Hanafy et al., 1986; Asmatullah and Aslam, 1999].

None of the three mothers reported tobacco or alcohol

use, and none reported taking prescription, over-the-counter

or folk medications. All three mothers immigrated from

Mexico, had undocumented US immigrant status (i.e., they

did not had a US visa, or other immigration document), and

sought prenatal care late in their pregnancies.

INSPECTIONS BY THE STATE

DEPARTMENTS OF AGRICULTURE

In 2005, the grower’s Florida and North Carolina farms

were inspected by FLDACS and NCDACS, respectively. A

large number of health and safety violations were identified

and the grower received among the largest fines ever imposed

by FLDACS and NCDACS ($111,120 and $184,500,

respectively). Violations included failure to prevent workers

from entering pesticide-treated fields before REI expiration,

failure of pesticide handlers to understand all pesticide label

requirements, and failure to provide water either to wash off

pesticides or to drink.

190 Calvert and Higgins
However, the grower contested the fines in both states,

arguing that most of the alleged violations were based on

records voluntarily recorded and retained by the grower.

Although records are required that document when and what

pesticide was applied to a given field, growers are not

required to keep records on the movement of workers into

that field. The grower voluntarily kept records to track the

fields where the case mothers may have worked on a

given day, but argued that the records were often imprecise.

For example, the records might list 22 fields where the case

mother may have worked on a given day. It is unlikely that the

case mother worked in all 22 fields. So if one or more of the 22

fields were under a REI for that entire day, it is possible that

the case mother was not required to work in any recently

treated field. In contrast, the regulatory agencies used those

records to support their citations. So in the 22-field example,

if only one field was under an REI for that given day, the

regulatory agencies may have cited the employer for

allegedly allowing the case mother to work in that field.

Thus, the grower argued that the records were misused

and misinterpreted since one could not use the records

to conclusively determine where workers worked on a

given day. The grower also explained that some fields were so

large that employees could be safely working in one area and

pesticides applied acres away in the same field.

Note that according to records supplied by the grower,

case 3 worked for 2 days during the period of organogenesis

when all the fields where the case was scheduled to work were

under an REI for the entire day. In addition, case 3 worked for

three additional days during the period of organogenesis

when all the fields where she could have labored were under

an REI for several identical hours, suggesting that the case

could not have escaped working in violation of the REI

during those hours. All five of these days involved the Florida

farm locations. In contrast, for cases 1 and 2, for each day

worked during the period of organogenesis there was always

at least one field where the case was scheduled to work that

was not under an REI for that day. However, case 1 reported

that she was occasionally sprayed with pesticides while

working in the fields but it is not known if she was directly

sprayed during the period of organogenesis [Chelminski and

Higgins, 2006].

Judges in both Florida and North Carolina agreed with

the grower’s arguments and cited the gap in pesticide law that

does not require growers to keep accurate records of when

and in what fields farmworkers work [Layden, 2007]. The

judge in North Carolina recommended that the number of

violations and the level of fines be reduced to $6,000.

Subsequently, the North Carolina Pesticides Board issued a

fine of $21,000 in March 2008 for 42 of the original 369

violations [Collins, 2008] and an additional fine of $3,000 in

February 2009 for another 6 of the original 369 violations

[Layden, 2009]. The judge in Florida ordered that the number

of violations be reduced and the level of fines be lowered to

$8,400. To our knowledge, no subsequent regulatory or

judicial action was taken in Florida with respect to the

violations and fines.

INSUFFICIENT EVIDENCE TO ESTABLISH

A CAUSAL RELATIONSHIP

The SENSOR-Pesticides report describing the cluster

was prepared by representatives from NIOSH, EPA,

FLDOH, NCDPH, and the National Center on Birth Defects

and Developmental Disabilities [Calvert et al., 2007]. It

concluded that the available evidence was inadequate to

establish a causal relationship between the birth defects and

pesticide exposures. For one, the complete cohort of female

farmworkers employed by the grower could not be

ascertained and studied due to lack of cooperation from the

grower (956 farmworkers were employed at the Florida

location and 500 at the North Carolina location, 20% of

whom were women). It addition, a genetic etiology could not

be ruled out for cases 2 and 3. Furthermore, as explained in

detail above, information on pesticide exposure was based on

the growers records and could be inaccurate. Biomonitoring

and environmental sampling were not performed during the

period of organogenesis to confirm pesticide exposure.

Additional limitations were the small number of cases, and

despite suggestive evidence in animals, published epidemiologic studies of human birth defects and the pesticides of

concern were not known to exist.

Nonetheless, this cluster pointed to the need to protect

farmworkers from pesticide exposures by: (1) increasing

efforts to publicize and comply with both the EPA WPS and

pesticide label requirements; (2) enhancing procedures to

ensure pesticide applicator competency, and; (3) recommending that growers be prescribed to adopt work practices

to reduce pesticide exposures. In October 2005, the grower

voluntarily agreed to discontinue using five pesticides

(methamidophos, mancozeb, metribuzin, oxamyl, and avermectin) associated with teratogencity in animals.

LEGISLATION PASSED IN

NORTH CAROLINA

Following the investigation of this birth defects cluster,

NC DPH, initiated efforts to highlight pesticides as an

important issue needing more attention, including the

drafting of a proposal to create a Governor’s task force. In

these efforts, the NC DPH received advice and technical

support from the North Carolina Agromedicine Institute/

Southern Coastal Agromedicine Center, and federal partners

(NIOSH/CDC and EPA). These efforts led in February 2008

to Governor Mike Easley assembling the ‘‘Governor’s Task

Force on Preventing Agricultural Pesticide Exposure’’ which

Using Surveillance to Promote Occupational Health 191
consisted of key North Carolina governmental leaders in

health and agriculture. The purpose of the task force was to

examine current pesticide regulations and pesticide use

practices and to make recommendations to protect the

health of agricultural workers. The task force presented its

recommendations in April 2008 [Devlin et al., 2008]. Many

of these recommendations were made into law through

legislation passed in North Carolina in July 2008 that resulted

in funding to: (1) strengthen surveillance; (2) improve the

quality of pesticide compliance inspections; and (3) increase

and improve pesticide safety training. The funding to the NC

DPH will: (1) continue support of surveillance of acute

pesticide poisonings and includes an annual appropriation of

$79,000 to hire an epidemiologist to operate the state-based

pesticide poisoning surveillance program; (2) provides a

one time $50,000 allocation that will be used to educate

physicians about pesticide poisoning and the state’s mandatory reporting law; and (3) support adaption of the current

surveillance database to one that is compatible with the

National Emergency Disease Surveillance System (NEDSS).

Task force recommendations also resulted in enactment

of new anti-retaliation and recordkeeping laws to protect

agricultural workers. The new law gives agricultural workers

the same protections against retaliation in the workplace as

are granted to workers employed in other industries. As such,

the law now protects agricultural workers from retaliation

who file a workers’ compensation claim, complain about

working conditions, and initiate workplace investigations.

The law also requires more detailed record keeping with

respect to pesticide applications. When a pesticide application is made, the time and day when the application was

completed must now be recorded. The federal WPS requires

pesticide applicators to record the time and date when a

pesticide is to be applied, but not when the application was

completed. The REI is calculated using the time the

application is completed. By knowing the time and day

when the application was completed, the time and date when

entry into a treated area is permitted can be accurately

determined. Also, pesticide application records for both

restricted use and general use must be retained for 2 years,

whereas the retention period was 30 days for general use

pesticides before this law was passed. Unfortunately the new

law does not require detailed records on the dates and times

when an agricultural worker works in specific fields.

As for Florida, in 2006 the state legislature agreed to add

10 new pesticide inspectors to FLDACS to monitor pesticide

use and enforce pesticide regulations on Florida farms

[Gomez, 2006]. The number of FLDACS agricultural

inspectors to enforce pesticide regulations currently stands

at 40 [Bryant, 2009]. There are 47,000 farms in Florida

[US Department of Agriculture, 2009]. North Carolina has

23 agricultural inspectors to enforce pesticide regulations

on its 53,000 farms [US EPA, 2009; US Department of

Agriculture, 2009].

CONCLUSIONS

This report highlights the important and positive impacts

that can occur through surveillance findings. The most

important use of surveillance data is to guide prevention

activities, including regulatory, enforcement, consultative,

and educational interventions [Thacker and Berkelman,

1988]. As demonstrated by this case study, it is important

to continue to support and improve surveillance programs for

pesticide-related illnesses.

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