For decades, studies have suggested an increased risk of prostate cancer among farmers. Farmers are generally more healthy than the overall population, with lower rates of cardiovascular disease, diabetes, mortality, etc. (Blair et al., 2005).  However, farmers have an increased risk of prostate cancer which may be explained by pesticide exposure, or possibly by other farm- or non-farm related exposures. Comparing the incidence of prostate cancer in farmers with members of the general population, researchers have estimated that farmers have a roughly 20% increased risk of this cancer (Koutros et al., 2010a). Case-control analysis within the AHS suggest exposure to several organophosphate pesticides may be related to prostate cancer, but only among men with a family history of the disease (Alavanja et al.. 2003). Additional follow-up within the AHS cohort corroborate this initial finding (Mahajan et al., 2006 and 2007; Christensen et al., 2010). The association of prostate cancer with certain pesticide exposure varies by family history of prostate cancer, and molecular epidemiology studies are underway that may shed light as to the potential role of genetic variation in the association. This work is not yet complete.  However, initial investigations recently released indicate that a genetic variation in genetic region 8q24 may partially explain the association between pesticide exposure and prostate cancer (Koutros et al., 2010b).  Although these genetic variations do not fully explain the cancer relationships within a family, so other shared environmental exposures may play an important role. Overall, however, across studies published, results are not consistent, possibly due to differing study designs used.

In investigations of farmworker populations, prostate cancer associations have also been found. For example, Mills and Yang (2003) investigated prostate cancer risk among farmworkers in California, and concluded that high levels of exposure to various types of pesticides left Hispanic workers with an elevated risk of prostate cancer.

Recently, AHS researchers produced a new analysis of pesticide exposure and prostate cancer, this time focusing upon more aggressive cases of the disease (Koutros et al. 2012).  For the purposes of this study, aggressive prostate cancer was defined as a distant stage (tumor tissue outside of prostate), and advanced grade (more poorly differentiated cell structure) indicative of a more advanced disease. Researchers observed an increased risk of aggressive prostate cancer among those who reported using higher amounts of four pesticides over their working lifetime.  This work supports previous analyses noting links between specific organophosphate pesticides and prostate cancer. It also extends an understanding of the possibility of a link with the aggressive form of the disease, which is thought to have a different set of causal factors than slow-growing tumors. This is the first study on an aggressive disease, and more work is needed to distinguish clear causal pathways.  However the study is supportive of previous work concerning an apparent increased risk of prostate cancer among pesticide applicators enrolled in the AHS.

Lung Cancer

There have been studies on the link between pesticide exposure and lung cancer. Alavanja et al. (2004), reported a positive association between four pesticides and pesticide exposure among the AHS cohort. In this study, exposure to these pesticides was associated with lung cancer risk in the cohort, despite the fact that, in general the lung cancer risk for the cohort is lower than the population as a whole. Other studies have also shown an association between pesticides and lung cancer in the AHS cohort (Beane-Freeman et al., 2005; (Lee et al., 2004).

      13.1.10. Non-Cancer Health Effects

Many epidemiological studies have posited a non-cancer chronic health consequence of pesticide exposure, however none have been determined to be causal in nature at this time. Preliminary investigations have identified elevated risks of respiratory and neurological effects; as these are preliminary investigations other explanations for these effects cannot be eliminated at this time.  However, some of the more plausible hypotheses involve a potential role of pesticide exposure and some neurological outcomes in adults such as Parkinson's disease (PD) and general neurological health (discussed below).   To the extent that the proposed changes to WPS rules reduce chronic exposure to pesticides, they may reduce the incidence of these chronic health effects as well.

Neurological Function

The possible connection between pesticide use and symptoms of Parkinson's disease (PD) has spurred a great deal of research. Using the AHS cohort, Kamel et al., (2007), investigated the hypothesis that PD is associated with pesticide exposure. Study participants included licensed private pesticide applicators and spouses, enrolled in the AHS from 1993 through 1997 and contacted for a follow-up study from 1999 through 2003. They report a positive association of PD in those who reported ever using pesticides, and a "strong association" with PD for those who personally applied pesticides. Cumulative lifetime days of use was associated with a dose-response relationship in cases diagnosed after the beginning of the study, but there was no association with a dose-response function and cases diagnosed prior to the study.  This study has recently been updated with physician-diagnosed cases of PD, as opposed to participant self-reporting of PD, and authors reported statistically significant 2.5-fold increased odds of PD if participants used either paraquat or rotenone (Tanner et al., 2011).

In a review study on the non-cancer effects of pesticides mentioned earlier, Sanborn et al. (2007) evaluated prior work on the association between Parkinson's symptoms and pesticide exposure, and reported a positive association in 15 out of the 26 studies reviewed.  The authors conclude that these studies "provide remarkably consistent evidence of a relationship between PD and past exposures of pesticides on the job."

Sanborn et al. (2007) examined the non-cancer health effects of pesticides in a review, and found most (39/41) studies displayed a positive increase in one or more neurological abnormalities in association with pesticide exposure. These outcomes ranged from neurodevelopmental effects in preschool children, general malaise and mild cognitive function, minor psychological morbidity, depression, suicide and death from mental disorders (Sanborn et al., 2007).  Kamel et al., (2007a), using the AHS cohort, found associations between neurological symptoms and lifetime pesticide exposure, with the greatest association for organophosphate pesticides.

In a study of the neurobehavioral performance in agricultural and nonagricultural Hispanic workers, Rothlein et al., (2006) examined the possible neurobehavioral effects of low-level chronic organophosphate pesticide exposure. Residues of these pesticides were found in a substantial portion of workers' homes. A significant correlation was observed between urinary metabolite levels and total organophosphate house dust levels. Poor performance on five neurobehavioral tests was associated with higher levels of the average combined thiomethyl metabolites in adult farmworkers. According to the authors, the correlation found between environmental contamination and levels of urinary metabolites further demonstrates the take-home pathway of pesticide exposure and the need for better home hygiene practices.

Research on the neurological effects of pesticide exposure continues.   Three recent studies (Rauh et al., 2011; Engel et al., 2011; and Bouchard et al., 2011) have investigated the relationship between prenatal exposure to organophosphate pesticides including chlorpyrifos and neurological effects in children through the age of 7 years.  Another recent study (Rohlman et al., 2011), reviews the possible relationship between adult occupational exposure to pesticides and adverse neurological symptoms.  The authors acknowledge uncertainties present in the data at this time which limit causal inference including a clear biologically plausible mechanism of action, among other study characteristics.

Respiratory Function

Several studies have shown linkages with both permanent and transitory (but chronic) respiratory effects. Asthma is a temporary inflammation of the lungs, often caused by an environmental trigger, which leads to coughing, wheezing and shortness of breath. Although the symptoms of asthma last for minutes or days, being susceptible to asthma attacks is a lifelong problem, and several studies have shown an association between pesticide exposure and asthma.  Hoppin et al., (2008) reported an association between pesticide exposure to a range of pesticides and asthma in farm women, despite the fact that growing up on a farm reduced the likelihood of asthma attacks. This study focuses on the spouses of pesticide applicators and may show an important effect from generalized agricultural pesticide exposure to families and farmworkers, rather than exposure as a pesticide applicator.   An association has been reported for children, as well. Salam et al., (2004) describe a range of risk factors related to childhood asthma. Among those risk factors were pesticides, and other farm exposures. The effects were largest for children with early onset asthma. An international study on childhood exposure to pesticides in Lebanon (Salameh et al., 2003) also reports a relationship between exposure and respiratory symptoms.

Studies have also reported an association between pesticide exposure and chronic bronchitis, an inflammation of the air passages of the lungs. While acute bronchitis usually has symptoms over a short term, chronic bronchitis is a recurring chronic obstructive pulmonary disease that makes it difficult to breathe for months at a time, with coughing that expels sputum from the airways.  Hoppin et al. (2007) reports a statistically significant association between eleven pesticides and chronic bronchitis among the AHS cohort  -  an association that was stronger among those with a high pesticide exposure event.

      13.1.11. Summary of Chronic Exposure and Risks

Overall, epidemiological or human study data do not suggest a clear cause-effect relation between specific pesticide exposure and certain chronic health outcomes.  However, the totality of national and international research efforts and initial research results in conjunction with plausible hypotheses, taken together, suggest that pesticide exposure may result in chronic adverse health effects beyond those mitigated as a result of chemical-specific label requirements and standards.

                 11.1. Non-Quantified Benefits of Avoiding Potential Chronic Risks

The proposed changes to the WPS are designed to reduce occupational exposure to all pesticides, as well as reduce the non-occupational exposure to the families of workers and handlers.  There is sufficient evidence in the peer-reviewed literature to suggest that reducing pesticide exposure would result in a benefit to public health through reduced chronic illness (Section 6.6 above).  In general, while there is sufficient evidence to suggest associations between exposure and illness, the literature does not provide sufficient data to quantify health effects of specific pesticides for use in a benefits analysis.   The totality of findings suggests the proposed WPS changes are a way to reduce overall pesticide exposure, which will result in an overall benefit to occupational health.

The health effects potentially caused by occupational pesticide exposure can have dramatic effects on the health and welfare of workers and handlers who suffer these diseases.  These illnesses do not only affect those who become ill, but they also may require extensive caregiving by family members or others. It is also important not to underestimate the effects on those stricken with illness.  Parkinson's disease, for example is a progressive disease characterized by tremors, rigidity and stiffness of the limbs, instability and falling, all of which result in difficulty performing everyday functions (Parkinson's Disease Foundation).  Non-Hodgkins lymphoma is a cancer that starts in the immune system, with symptoms of swollen lymph nodes, weight loss, fever, weakness, respiratory distress, drenching night sweats, and pain.  Treatment for NHL, has a range of side effects that can also generate substantial symptoms (National Cancer Institute, 2007).  In addition to the symptoms of NHL and the treatment, the disease is often fatal.  The five year survival rate for NHL is only 70.2%, meaning that almost 30% of people diagnosed with NHL in 2003 died within five years (National Cancer Institute, 2011).

Because of the uncertainties in the number of illnesses that may be caused by, and therefore prevented by reduced pesticide exposure, it is impossible to derive quantified estimates of pesticide-specific benefits from illness reduction.   In the U.S., health care costs for chronic disease are great, in addition to the direct human cost of illness mentioned in the previous paragraph.  The additional medical costs for a patient suffering from Parkinson's disease have been estimated at over $10,000 annually (Huse et al., 2005).  NHL treatment costs have been estimated at over $5,800 monthly for aggressive NHL, and over $3,800 monthly for slower-growing NHL (Kutikova, et al.)  For prostate cancer, average cost of treatment over 5 and half years of the study was over $42,500 (Wilson et al.).   These costs are very high, especially so relative to the income for workers and handlers, and the value of reducing these illnesses is likely to be substantial, as well.  These costs are treatment costs, which is likely an under-estimate of the true cost of illness.

The next section details the break-even analysis methodology, which considers the value of potentially preventing some of these illnesses, using estimates of the willingness-to-pay to avoid illness or death.

                 11.2. Break-Even Benefit Analysis of Avoiding Potential Chronic Risks

In this section, EPA presents a "break-even" analysis.  This analysis shows that preventing a very small number of illnesses potentially associated with pesticide exposure could result in benefits to human health equal to or greater than the difference between the quantified benefits and the estimated costs of the rule.  As described below, preventing only a few pesticide-related illnesses annually, less than one percent of the cases of a handful of diseases, would generate enough in benefits to close the gap between the estimated cost of the WPS changes and the quantified estimate of benefits from reduced acute exposures.  The break-even number of cases is quite low, because the diseases under consideration can have severe effects which persist over a long period of time, and the cost of health care is great.  For this exercise, we consider non-Hodgkin's lymphoma, prostate cancer, lung cancer, bronchitis, Parkinson's disease and asthma to demonstrate the potential benefits in the proposed rule from reducing exposures to chronic illnesses. These are the illnesses for which there is evidence of an association with pesticide exposure and for which credible willingness to pay estimates exist in the peer-reviewed literature or may be transferred.
      13.1.12. Background

The break-even approach uses EPA's estimates of monetized benefits for reduced acute exposures, and subtracts them from the estimated annual compliance costs of the proposed rule.  The resulting "net cost" enables one to work backwards to estimate what the benefits from reduced chronic exposure would need to be for the total annual benefits of chronic illness reduction to equal costs.  A break-even analysis is a useful alternative when quantifiable data are lacking (OMB, 2003).  Although we cannot quantify net benefits of chronic disease avoided, we can estimate the number of cases that would need to be prevented by WPS changes to cause the net benefits to become positive.  This estimate then can be assessed for plausibility.  It can also be a useful step to ensure that unquantifiable benefits, like reduced chronic exposures to pesticides, are not ignored when weighing costs and benefits.

Break-even analyses have been used by EPA in the past when monetized estimates of all benefits could not be estimated.  The analyses in support of several rules from the EPA Office of Water used this approach to highlight benefits that could not be quantified (EPA, 2011; EPA, 2010b; EPA, 2006c; EPA 2005).  For these cases, the break-even analyses were based on prevented illness or fatalities when the number of illnesses or fatalities could not be estimated, similar to what is done here. These examples have most often reflected acute health effects with a known causal link to an environmental exposure, e.g., gastrointestinal distress as a result of bacterial contamination of water.  The break-even analysis here is based on associations between pesticide exposure and chronic disease, where causal links are considered in the peer-reviewed literature (see Section 6.7).

The costs of environmental regulations are traditionally much simpler to quantify than benefits to health or the environment. Costs of equipment, time to train and build knowledge can be easily estimated. However, environmental or human health benefits are often difficult to quantify due to data limitations, as noted above, or the non-pecuniary nature of these benefits.  However, as noted in Section 6.5 the human epidemiology research reporting links between pesticide exposure and human health outcomes indicates that some degree of public health benefits will likely accrue as a result of pesticide exposure reduction from changes to the WPS.

Ideally, EPA could quantitatively estimate the public health benefit of pesticide exposure reduction through updated WPS requirements through reduced disease burden. However, we are unable to quantify the benefits from reducing chronic health effects for several reasons. While exposure reduction is an anticipated outcome from the WPS rule, it is difficult to quantify the magnitude of the exposure reduction because the interventions are indirect, i.e., they influence behavior associated with pesticide safety practices.  Similarly, while statistical associations have been observed in studies which estimate the relation between pesticide exposure and chronic health outcomes such as cancer, as noted in Section 6.5, the causal nature of these associations have not yet been determined; thus calculating attributable risk, or the magnitude of the chronic health risk reduction expected as a result of pesticide exposure reduction, is premature at this time. It is likely that pesticide exposure may be one of multiple risk factors for certain disease outcomes in the population (i.e., there is a multi-factorial web of disease causation), however it is plausible that some instances of disease (specific cases) could be attributable to pesticide exposure.  Epidemiological research is particularly difficult when the subjects are farmworkers and their families.  Relative to other studies of the effects of occupational exposure to chemicals, studies based on farmworkers are more difficult because it is harder to estimate exposure to specific pesticides, because they were not applied by the worker, and may not have been applied by the handler (Zahm and Blair, 2001 and 1993).  Exposure estimation through work history is also difficult with this mobile population, making it harder to identify exposure based on available application data (Zahm et al., 2001, Zahm and Blair 1993).

The break-even analysis is meant for illustrative purposes. The analysis is designed to demonstrate the magnitude of potential health risk reduction which would be necessary to equilibrate the total WPS costs using traditional and conservative assumptions from the environmental economics peer-reviewed literature.

In Section 6.6, EPA presented a review of the epidemiology literature in which authors report observations between pesticide exposure and certain chronic health effects.  Included in that discussion is information on the Agricultural Health Study (AHS), a large prospective cohort study of about 90,000 farmers and their spouses initiated in the early 1990's.  The study is recognized for its design and robustness, with exposure measurements that have been extensively validated.  Because of these characteristics and strengths, it is appropriate to use the results and findings of this study in evaluating pesticide risks. OPP has been systematically evaluating this study in collaborative projects with the AHS investigators with respect to algorithms, exposure assumptions, and other critical information.  OPP is developing a framework for interpreting epidemiological data and integrating the results into the overall data that is grounded in sound scientific principles and use of Bradford Hill criteria for evidence of causation.  The work products and ideas that OPP has generated and presented have been well received by recent Scientific Advisory Panels and various stakeholders. These data inform hazard identification and characterization, although exposure profiles and use practices have changed over time such that past and current exposures differ from current and future pesticide practices. Therefore, while studies such as the AHS are helpful for hazard characterization, additional information outside of any one epidemiology study may be needed to assess current, real-world exposure potential. The putative associations suggested in epidemiology studies like the AHS can help in evaluating potential health outcomes associated with exposures and assist in conducting an economic evaluation of possible benefits from reducing exposure through an enhanced worker protection standard.

      13.1.13. Method

For the acute estimates earlier in this chapter, the number of cases prevented was found by evaluating descriptions of the incidents that led to the pesticide exposure.  For this break-even analysis of the chronic exposure, the number of cases prevented will not be known.  At the end of the process we will search for the percentage of cases that must be prevented for the benefits to exceed the costs, and consider whether the number of cases reduced is plausible for the farmworker and handler population.  For simplicity, we will generally assume the same rate reduction for all diseases and their fatal effects, if any, although it is likely that different exposure-response profiles exist for specific pesticide-chronic health effect association.

As discussed in Section 6.6, there are many health effects that may be associated with chronic, non-specific pesticide exposure.    For this break-even exercise, however, we will consider only a few illnesses associated with chronic pesticide exposure: non-Hodgkin's lymphoma, prostate cancer, lung cancer, chronic bronchitis, Parkinson's disease and asthma.  Numerous observational studies have been performed evaluating pesticide exposure in association with these human health outcomes. While scientific consensus has not established these associations as causal in nature, evidence is suggestive of an association. For illustrative purposes, these health outcomes are identified for the break-even analysis.

It should be emphasized that the diseases (cancer, neurological diseases, and pulmonary effects) included here are chosen as representatives of the range of diseases that may result from chronic exposure to pesticides.  For example, there are a range of other cancers for which studies have shown an association in farmworkers (Mills and Yang, 2006a, 2006b), but the associations may not be as strong as the ones we have included here largely due to challenges of performing observational studies in the farm worker population.

To estimate the break-even number of prevented cases, we will begin with national data on disease incidence, which describes how many cases of disease can be expected to be diagnosed each year.

Next, we need an estimate of the benefit of reduced illness.  EPA's preferred approach is to use an estimate of "willingness to pay" (WTP) to reduce the risk of experiencing an illness (US Environmental Protection Agency, 2010).  As described in Freeman (2003), this measure consists of four components:

   * "Averting costs" to reduce the risk of illness;
   * "Mitigating costs" for treatments such as medical care and medication;
   * Indirect costs such as lost time from paid work, maintaining a home, and pursuing leisure activities; and
   * Less easily measured but equally real costs of discomfort, anxiety, pain, and suffering.

WTP represents the amount of money that an individual or group would pay to receive the benefits resulting from a policy change, without being made worse off.  There are other values excluded by using WTP as the metric.  WTP is usually characterized as a WTP for improved health outcomes for oneself, which is true here, as well.  This does ignore that people may also value the health of others, and place some value on seeing others protected, especially when they are a disadvantaged population, like farmworkers.  These altruistic benefits are not included in the WTP estimates presented here.

Typically WTP estimates will vary by the type of disease, because of differing health consequences and differing amounts of dread the disease imparts in the study subjects.  For example, WTP may be higher to avoid a fatality from cancer than from a car accident.  For many non-fatal diseases, direct estimates for WTP are not available.  In these cases, we will use benefits transfer to find estimates.  This involves applying available estimates of WTP for preventing illness to the relevant ones for the WPS changes, adjusting them if needed.

For cases of fatalities prevented, we value the benefits with the Value of a Statistical Life (VSL).  EPA currently recommends a default central "value of statistical life" (VSL) of $7.9 million (in 2008 dollars) to value reduced mortality for all programs and policies.  This value is based on a distribution fitted to 26 published VSL estimates (US Environmental Protection Agency, 2010).

The benefits for preventing chronic illness are simply the sum across illnesses of the value of prevention times the number of prevented cases, which are the prevented share (PrevShare) times the number of cases:
Chronic Benefits=iωi∙PrevCasesi=iωi∙PrevSharei∙Casesi
where ωi can be WTP for avoided illness i and VSL for avoided fatalities.  To perform the break-even analysis, the goal is to find the PrevShare that causes Chronic Benefits to be greater than or equal to the difference between the cost estimates of the rule and the estimated acute benefits.  The break-even point is where the benefits of the chronic equal the gap between the estimated cost (Cost) and the estimated acute benefits (Acute):
ChronicBE>= Cost-Acute.

The final step, then, is to find the prevented share that makes Chronic Benefits at least equal to the difference between the estimated costs and acute benefits, Chronic[BE].  A simplifying assumption is that PrevSharei is equal for all diseases, which means that the percentage reduction in illness is the same.  We do that here, with one exception: lung cancer.  The primary cause of lung cancer is smoking tobacco.  Although other environmental exposures combine with tobacco smoke to increase the risk of lung cancer, any changes to the WPS are likely to have little effect on cancer caused by smoking.  For that reason, we assume that the PrevShareLung Cancer is 10% of the PrevShare for other diseases.  This reduced rate is the lower end of the estimated 10  -  15% of lung cancers found in people who have never smoked (Thun et al., 2008).

      13.1.14. Data

To perform the break-even analysis described in the previous section, we need information on the number of illnesses annually for these diseases and the WTP to avoid suffering the illness.  The cost of the rule was estimated in Chapter 5 and the quantified acute benefits of the rule were estimated in Section 6.5.  The number of illnesses is available in the literature or publicly available.  Estimates of WTP are from the Economic Analysis for the Final Stage 2 Disinfectants and Disinfection Byproducts Rule (EPA, 2005) except for the WTP to avoid asthma, the estimate for which is taken from the academic literature (O'Conor and Blomquist, 1997).  The data used in the analysis are summarized in Table 6.8-1.

Non-Hodgkin's Lymphoma

The American Cancer Society (2012) estimates there are just over 70,000 new cases annually of non-Hodgkin's lymphoma, a cancer of the lymphatic system.  Of these cases, 30% (about 21,000) result in death (American Cancer Society 2012, based on Howlader et al., 2011).  An estimate of the WTP for reducing a case of non-fatal lymphoma of $4.6 million was derived in the Economic Analysis for the Final Stage 2 Disinfectants and Disinfection Byproducts Rule (EPA 2005).  The estimate was based on Magat et al. (1996), from which it was determined that the median risk-risk trade-off for contracting a curable case of lymphoma was equivalent to a 58.3 percent reduction in the risk of sudden death.  Thus, WTP for non-fatal lymphoma was calculated as 58.3 percent of the VSL.  Given the current estimate of VSL of $7.9 million, we estimate a mean WTP for non-fatal lymphoma of $4.6 million (VSL x 58.3%).

Prostate Cancer

Prostate cancer is a common cancer among American men and the second leading cause of cancer deaths behind lung cancer.  Based on CDC data from 2003  -  2007 (U.S. Cancer Statistics Working Group, 2010), there were about 203,000 cases of prostate cancer per year, on average.  The number of cases has been trending upward, with about 223,000 cases reported in 2007.  The American Cancer Society (2012) estimates that there will be 241,740 cases in 2012.  In addition, CDC reports about 29,000 fatalities resulting from prostate cancer on average, where fatalities have been declining (U.S. Cancer Statistics Working Group, 2010).  For this analysis, we use the relatively conservative figures of 223,000 non-fatal cases and 29,000 fatal cases of prostate cancer. In the Agricultural Health Study, although overall cancer incidence (all cancers combined) is lower than the general population, the incidence of prostate cancer is consistently higher than the general population (Alavanja et al., 2003; Koutros et al., 2010a).

An estimate of WTP to avoid curable prostate cancer is not available in the literature.  Therefore, we base our estimates on the WTP to avoid lymphoma.  Prostate cancer, however, is both a more common and less severe cancer than lymphoma, so a lower value for WTP is appropriate.  We estimate WTP to avoid prostate cancer as a fraction of the WTP for curable lymphoma based on the ratio of treatment costs for the two diseases.  Wilson et al. (2006) estimates the average annual treatment cost for prostate cancer to be $7,740. Based on Kutikova et al. (2006), the treatment costs for indolent non-Hodgkin's lymphoma are just under $46,000 per year, so the cost of treatment for prostate cancer is 17% of that for non-Hodgkin's lymphoma.  Using that percentage multiplied by the WTP to avoid lymphoma yields an estimate of WTP to avoid prostate cancer of $780,000.

This figure may be an underestimate.  It is based on the treatment cost for prostate cancer that may be low, considering several new treatment and drug regimes that are very expensive.  Further, some prostate cancers, particularly those that affect younger men, may be more aggressive and require more expensive treatment than those found in elderly men.

Chronic Bronchitis

Chronic bronchitis is one of the forms of chronic obstructive pulmonary disease, in which bronchial tubes of the lungs are inflamed, and results in a long-term cough, shortness of breath, excessive mucous, fatigue and wheezing, eventually severely restricting mobility and quality of life (US National Library of Medicine, 2012).

Chronic bronchitis is common, with 9.9 million diagnoses a year (Centers for Disease Control, 2012a), but only a few deaths per year (639 from the same source). These figures are misleading, because the CDC criterion for a diagnosis is that a patient has been identified within the previous 12 months with chronic bronchitis by a physician.  The 9.9 million diagnoses are more likely to reflect the number of patients with the disease, rather than new cases that occur in a given year.  We have been unable to find good estimates for the incidence of the chronic bronchitis, and using the prevalence would be misleading, so for this analysis, we will only include the few fatalities.  This is disappointing, because reduced lung function can have important impacts on quality of life, and past EPA economic analysis has provided estimates of the WTP to avoid chronic bronchitis.  The Economic Analysis for the Final Stage 2 Disinfectants and Disinfection Byproducts Rule (EPA 2005) did provide estimates of the WTP of $800,000 to avoid chronic bronchitis, based on Viscusi et al. (1991).

Parkinson's Disease

Parkinson's disease, a progressive neurological disease is diagnosed about 60,000 times annually (Parkinson's Disease Foundation 2010).  Parkinson's patients have higher mortality rates than the general population and the CDC classifies Parkinson's disease as the 14[th] leading cause of death in the United States, but any death is usually an indirect result of Parkinson's disease.  The progressive neurological effects of Parkinson's, such as swallowing problems which lead to undernourishment and higher risk for aspiration pneumonia, can reduce longevity (Parkinson's Disease Foundation 2010 and University of Maryland Medical Center 2009).  Because of these complications, we take a conservative approach in this break-even analysis, and ignore the fatalities for Parkinson's disease. Similarly, there was no available estimate of WTP to avoid Parkinson's disease.  We propose to use the WTP for chronic bronchitis (above) for the WTP for Parkinson's disease, because in some ways the effects on quality of life are similar: restricted mobility, difficulty in everyday tasks and activity, for example.  The WTP to avoid chronic bronchitis is $800,000, which we will use for Parkinson's disease.

There are reasons to think this value is an underestimate.  First, chronic bronchitis can be treated, and sometimes cured, while Parkinson's disease is a permanent and progressive disease.  Second, there are other values we could use for benefits transfer in this case.  The WTP for lymphoma above was based on a study by Magat et al. (1996), which compared risk-risk tradeoffs for curable disease and death, in that case for lymphoma.  That same study also included a non-cancer disease, peripheral neuropathy.  Peripheral neuropathy is damage to the peripheral nervous system that shares some effects with Parkinson's disease, such as loss of strength, reduced mobility, and activity restrictions.  Using the method EPA used for estimating WTP for avoiding lymphoma, would result in an estimate of WTP to avoid peripheral neuropathy of about $3 million.  To be conservative, we use the smaller value of $800,000 here. Moreover, possible fatalities of Parkinson's disease are not included in the analysis.

Lung Cancer

Lung cancer is the leading cause of cancer deaths in the United States, and the third most common cancer after prostate and breast cancer (Center for Disease Control, United States Cancer Statistics, 2012).   In 2012, the CDC expects about 226,000 new cases of lung cancer to be reported.  Death resulting from lung cancer is very common, with the five year survival rate of only 15.9% (National Cancer Institute, 2012).  Both the incidence and number of deaths from lung cancer have been trending down slightly over time (National Cancer Institute, 2012).  Recent data suggest an estimate of 190,000 annual cases that will result in a fatality within a few years, and 36,000 survivable cases.  As mentioned above (Section 6.8.2), we will assume that lung cancer preventions happen at 10% of the rate for the other diseases for this analysis, which roughly corresponds to the share of lung cancer among non-smokers.  This is because changes to the WPS are not expected to have large changes on cancers caused by the primary risk factor, which is smoking.

There are no estimates of WTP for reducing the number of cases of lung cancer in the peer-reviewed literature that are appropriate for this rule.  Therefore, we follow the practice in the analysis for EPA's Radon in Drinking Water Health Risk Reduction and Cost Analysis (1999) and transfer the WTP to avoid chronic bronchitis as a measure of the WTP to avoid non-fatal lung cancer.  This will be the same value ($800,000) used for Parkinson's disease, because they come from the same source, the WTP to avoid chronic bronchitis from the Economic Analysis for the Final Stage 2 Disinfectants and Disinfection Byproducts Rule (EPA 2005).

 Asthma

Atopic asthma, in which an external trigger, such as dust or an allergen, causes periodic difficulty in breathing and airway blockage (Akinbami et al., 2012) , is another common respiratory ailment that has been associated with pesticide exposure (Hoppin et al., 2008)).  Asthma is very common, with 24.6 million people diagnosed by 2009 (Centers for Disease Control, 2012b).  That figure reflects people who have been diagnosed over several years, and asthma does not necessarily occur every year, even though it is a chronic disease.  CDC estimates that number of asthma cases grew by 4.3 million from 2001 through 2009 (Centers for Disease Control, 2011).  Using that number, this analysis will assume new cases of asthma are 478,000 annually, which is the rounded number of new cases from 2001  -  2009 divided by nine years.  Asthma attacks can also be fatal  -  in 2009, there were 3,388 deaths caused by asthma (Centers for Disease Control, 2012c).  We will round that figure to 3,400 cases per year for this analysis.

The WTP for avoiding asthma is based on O'Conor and Blomquist (1997).  Using a 3% discount rate to transform their annual estimate for WTP of $2,200 to a perpetuity to represent preventing development of asthma over a lifetime yields a WTP to prevent asthma of about $73,000 per case.

Table 6.8-1.  Information for Calculating Break-Even Number of Cases Avoided
                                    Disease
                           WTP to Avoid Disease, ωi
                                    ($1000)
                                 Annual Cases
Curable Non-Hodgkin's Lymphoma
4,606
49,000
Fatal NHL
7,900
21,000
Curable Prostate Cancer
780
223,000
Fatal Prostate Cancer
7,900
29,000
Parkinson's Disease
800
60,000
Curable Lung Cancer
800
36,000
Fatal Lung Cancer
7,900
190,000
Fatal Bronchitis
7,900
640
Asthma
73
480,000
Fatal Asthma
7,900
3,400
Source:	EPA, 2005; American Cancer Society (2012); U.S. Cancer Statistics Working Group (2010); Parkinson's Disease Foundation (2010); National Cancer Institute (2012); Centers for Disease Control, (2012a, 2012c); O'Conor and Blumquist (1997); EPA calculations

      13.1.15.     Break-Even Estimation

In Chapter 5, the costs of proposed WPS changes were estimated to be between $62.1 million and $72.9 million per year.  To find the break-even point, we need to find the reduction in illness that closes the gap between the estimated costs and the quantified acute benefits.  For this analysis, we will report a reduction in illness that generates benefits of at least the difference between the high value of the estimated costs ($72.9 million) and estimated acute benefits of $11.4 million, for a difference between estimated costs and quantified benefits of $61.5 million.

Reducing the national rate of these illnesses by 0.006% (and the rate of lung cancer by 0.0006%) is more than enough to provide benefits from reduced chronic illness that close the high estimate of the gap between costs and quantified benefits.  This reduction in illness would have an estimated benefit of $64.6 million dollars annually.  The results here obviously change based on assumptions about under-reporting of acute pesticide incidents, because that changes the estimate of acute benefits.  If we were to assume that there was no underreporting, then the acute benefits estimate would be about $2.8 million (See Table 6.5  - 11).  In that case, a reduction of 0.007% (0.0007% for lung cancer) would suffice, since the estimated $75.3 million  in benefits is more than the total high-end costs estimate of $72.9 million..  The reduction to break-even with only $2.8 million in acute benefits is about 0.0065%, and about 0.0059% to break even with a gap of $61.5 million.

Reducing the rate of illnesses through pesticide exposure reduction by 0.006% would reduce the number of non-Hodgkin's lymphoma cases by an average of 2.94 non-fatal and 1.26 fatal cases per year; the number of prostate cancer cases by an average of 13.38 non-fatal and 1.74 fatal cases per year; the number of Parkinson's cases by 3.6 per year; reduce the number of fatal bronchitis cases by 0.04 per year, and the number of cases of asthma by 28.8 cases, and fatal asthma cases by 0.20 per year.  Reducing the number of lung cancer cases by 10% of the reduction in other diseases, or 0.0006%, reduces the number of lung cancer cases by an average of 0.22 non-fatal cases and 1.14 fatal cases per year.

Of course, those percentage reductions are based on the number of chronic illness cases nationally, and the WPS changes will primarily effect a much smaller population, farmworkers and handlers.  Although the number of cases reduced to generate break-even chronic benefits will not change, they will represent a higher percentage of illness among this smaller population, which we describe below.

It is reasonable to think that incidence rates of these diseases may be higher for the agricultural community than the general public, because of the associations between pesticide exposure and disease described above and in Section 6.5.  However, we do not make that assumption here.  Instead, we assume that the worker/handler face illness equal to their share of the population.  The share is about 0.75%, based on the 2,323,000 farmworkers and a U.S. population of 308,700,000 (Census Bureau, 2011). Even so, the reduction in cases among farmworkers required to reach the break-even point is small in comparison to the number of expected cases.  A reduction in these illnesses of just under 0.8% (0.08% for lung cancer), will generate $64.8 million in benefits, more than required to reach the break-even point.  Across all diseases, the reduction is about 53 cases annually out of over 8,000 cases that might occur.  Table 6.8-2 shows the calculations for farmworker cases.  The estimated farmworker cases are 0.75% of the annual cases for the United States, and the break-even cases are the number of cases that prevented to reach the breakeven point.  In dollar terms the $64.8 million per year to break even represents an annual WTP per farmworker of less than $28.

      Table 6.8-2:  Illness Avoided among Farmworkers for "Break-Even" Analysis
Disease
                                 Annual Cases
                                   Incidence
                                (per 100,000) 1
                         Annual Cases Farmworkers[2]
                        "Break-Even" Avoided Cases
Curable Non-Hodgkin's Lymphoma
                                    49,000
                                     15.9
                                      369
                                     2.95
Fatal NHL
                                    21,000
                                      6.8
                                      158
                                     1.26
Curable Prostate Cancer
                                    223,000
                                     72.2
                                     1,678
                                     13.42
Fatal Prostate Cancer
                                    29,000
                                      9.4
                                      218
                                     1.75
Parkinson's Disease
                                    60,000
                                     19.4
                                      451
                                     3.61
Curable Lung Cancer
                                    36,000
                                     11.7
                                      271
                                    0.22[3]
Fatal Lung Cancer
                                    190,000
                                     61.5
                                     1,430
                                    1.14[3]
Fatal Bronchitis
                                      640
                                    3,207.0
                                       5
                                     0.04
Asthma
                                    480,000
                                    5,507.0
                                     3,611
                                     28.89
Fatal Asthma
                                     3,400
                                      1.1
                                      26
                                     0.21
Source:  EPA calculations.
[1]	Calculated as the number of annual cases divided by the U.S. population of 308,700,000 (US Census Bureau, 2011).
[2]	Based on incidence rates for farmworkers being equal to the nation as a whole.  The actual incidence rates may be higher; see the text.
[3]	Rate of Reduction for lung cancer is  only 10% of the reduction rate for other illnesses; in this case a reduction of 0.08% for lung cancer and 0.8% for the other diseases

It is important to consider whether the number of cases required for the break-even analysis is plausible.  As discussed above Table 6.8-2, the number of cases needed to reach the break-even point is small relative to the number of cases we estimate in the farmworker population, even when we assume that their rate of disease is equal to the population at large.  As discussed in Section 6.6, there is a possible association between the diseases discussed here and pesticide exposure, so farmworkers exposed to pesticides may be more likely to develop these diseases.  The next few paragraphs show that reducing rates of disease slightly will reach the break-even point, even if rates for farmworkers are not reduced to the level of the general population.  For this task, we will be using estimates of incidence rates of the three diseases, based on the AHS.  The AHS cohort consists of certified pesticide applicators and their spouses.  This cohort is healthier, better educated and wealthier than the farmworker population in general.  Although farmworkers and the certified applicators in the AHS study both face occupational exposure to pesticides, the exposure pattern can be quite different: farmworkers may be more likely to be exposed in the field while engaged in activities other than applying pesticides.   Pesticide handlers in the farmworker community do, however, share similar exposure potential to certified applicators on farms. Farmworkers may also be less aware of when they may be exposed than are applicators and less knowledgeable about how to protect themselves against pesticide exposure than applicators who have gone through the certification process.  Because of these differences in occupational exposure, it is unknown whether farmworker exposure is higher or lower than the AHS cohort.  Using AHS results for estimating farmworker incidence rates implies that results are subject to considerable uncertainty, but there is no clear bias in these estimates.

For prostate cancer, Alavanja et al. (2003) reported a point estimate for the standardized incidence ratio of 1.14 for the AHS cohort with a confidence interval of 1.05 to 1.24.  Using the 1.14 point estimate means the AHS cohort was 1.14 times more likely than the general population to develop prostate cancer, even though the overall rate of cancer is lower among the AHS population.

If we apply the 1.14 incidence ratio to farmworkers, that suggests farmworkers are 14% more likely to develop prostate cancer than the population in general.  We estimated the incidence rates shown in Table 6.8-2 by dividing the number of cases per year by the U.S. population; for prostate cancer these were 223,000 cases a year that are treatable, and 29,000 that result in death.   Because only males get prostate cancer, the incidence rate among males is twice as high, with 223,000 cases is about 144.5 per 100,000.  If the incidence rate were 14% higher for farmworkers, it would be about 164.7 cases per 100,000.  At the higher rate, we should expect about 1,913 cases annually in the farmworker population, even if we assume that only half of farmworkers are men, which is an underestimate.

The break-even number of cases of non-fatal prostate cancer with a 0.8% reduction among farmworkers is 13.42 annually.  To reach this level, the WPS changes would need to reduce the risk only slightly.  To reach the reduction of 13.42 cases annually would require a reduction in the incidence rate from 164.70 to 163.55, still well above the general population level.

A similar exercise can be done for fatal prostate cancers.  The incidence rate for the general population of men is about 18.8 per 100,000.  If farmworkers have a rate 14% higher, their rate would be about 21.4 per 100,000, resulting in about 249 cases per year.  The break-even number of cases is about 1.75 annually.  To reach the high-end reduction the incidence rate among farmworkers would fall from 21.4 to 21.3 per 100,000.  This result is consistent across the diseases considered here: all of the reductions in incidence rates among farmworkers are small, and with the exception of lung cancer and possibly chronic bronchitis, the reduced incidence rates remain higher than the general population.  For NHL, Koutros et al. (2010a) report a standardized incidence rate ratio of 1.17 among the AHS cohort for private applicators.  We estimate the incidence rate for treatable NHL to be about 15.9 per 100,000, using the same procedure as for prostate cancer.  If the incidence among farmworkers was 17% higher, it would be about 18.6 per 100,000.  To reach the reduction of 2.95 cases annually would change the incidence ratio from about 18.57 to 18.44 per 100,000.  For fatal NHL, the reduction in cases among farmworkers would reduce the estimated incidence rate from 7.96 to 7.90 per 100,000, still well above the rate we estimate for the general population of 6.8 per 100,000.  For Parkinson's disease, van der Markl et al. (2011) report an incidence ratio of 1.62 among the AHS cohort between those ever exposed to pesticides and those never exposed to pesticides.  That corresponds to an incidence rate of about 31.5 per 100,000 for farmworkers, compared to 19.5 among the general population.  Reducing the number of cases to get to the break-even point among farmworkers would reduce the incidence rate to about 31.3 per 100,000.  Among farm women in the AHS, Hoppin et al. (2008) reported an incidence rate ratio for asthma to 1.46 for those with any pesticide exposure relative to those without.  That yields an estimated incidence rate for farmworkers of about 227 per 100,000 for new asthma cases, compared to about 155 per 100,000 for the general population.  For fatal asthma, the estimated incidence rate would be about 1.6 per 100,000 for farmworkers, compared to about 1.1 per 100,000 for the general population.  Reducing cases to the break-even point among farmworkers would reduce the estimated incidence rate for asthma from 227 to about 226 per 100,000, while the fatal asthma incidence rate would remain unchanged at 1.6 per 100,000.  As with the other diseases described above, even after reductions in cases among farmworkers to reach the break-even point, the rate of these diseases among farmworkers is likely to remain well above that for the general population.

As mentioned above, there may be two exceptions for which the farmworker incidence rates are higher than the general population, even after reduction to the break-even point.  The two exceptions are for chronic bronchitis and lung cancer.  For chronic bronchitis, it is difficult to determine the correct rate among non-smokers.  Valcin et al., (2007) analyzes chronic bronchitis among non-smoking farm women in the AHS, and reports a prevalence  at 60% higher in association with six specific pesticides, and 58% higher with exposure to 3 or more pesticides, but does not compare them to a non-agricultural cohort.  Hoppin et al. (2007) reports an odds ratio for chronic bronchitis of 1.83 for AHS participants who have ever faced a high pesticide exposure event and elevated odds ratios for specific chemicals, but those are may not reflect the low-level chronic exposure relevant for the break-even analysis.  However, if we assume the farmworker rate is even 1% higher than the general population we see the same pattern: the number of cases among farmworkers can be reduced to the breakeven point, yet the incidence rate is the same as the general population.  Lung cancer does not fit the pattern of the other diseases here, because lung cancer rates are so low among the AHS cohort, less than half the rate of the general population (Alavanja et al., 2004).  The AHS cohort is less likely to smoke and are generally healthier than the general population, although this may not hold true for farmworkers.  If we reduce the number of cases among farmworkers by 0.08% (only 10% of the reduction for other diseases), the change in the estimated incidence rates for lung cancer are small, from 5.13 to 5.12 cases per 100,000 for curable lung cancer, and from 27.08 to 27.03 per 100,000 for fatal lung cancer.

In general, the reductions in chronic illness required to close the gap between costs and quantified acute benefits from the rule are small.  The reduction in cases relative to the farmworker population is plausible and it represents only a small change in the risk to farmworkers.

There are obviously many uncertainties, which is why the break-even analysis is necessary.  Relative to level of disease we might expect to see in the farmworker population, the break-even point where the benefits of the rule equal the costs can be reached by preventing relatively few cases.  One possible concern is that it is unclear when the prevented deaths would have occurred.  These diseases discussed here are chronic conditions that may have long latency periods of 5-15 years, i.e., a substantial amount of time between exposure and diagnosis and eventual death.  Using the estimates for farmworkers, discounting the VSL for 15 years at a 3% discount rate means the break even reduction would have to rise from 0.7% to 0.98%.  At a 7% discount rate, the reduction to reach the break-even point would reach 1.20%.

      13.1.16.     Break-Even Conclusions

The break-even analysis does show that preventing only a very small number of chronic illnesses can have very substantial benefits.  Based upon the best available information, this analysis demonstrates that a plausible reduction of about 53 pesticide-related chronic illnesses per year across the entire WPS occupational population of 2.3 million workers is all that is required to ensure benefits outweigh the costs of the WPS.

Chapter 7.  Paperwork Burden

Associated with changes in the WPS requirements, the affected entities are subject to paperwork burden.  The Paperwork Reduction Act requires federal agencies to estimate the burden of complying with regulations that require firms or individuals to file reports, maintain records, or otherwise incur a paperwork burden.  Agencies are likewise required to estimate their resources expended.  Because of the substantial changes in WPS requirements, EPA developed a new Information Collection Request (ICR) entitled, "Worker Protection Standard Training and Notification (Proposed Rule)" (EPA ICR no. 2491.01; OMB Control No. 2070-NEW, in conjunction with this action, using the same parameters and data as utilized in this Economic Analysis.  See Appendix B.

The total estimated annual respondent burden for this ICR renewal for respondents is 8,316,993 hours.  This is an increase of 6,541,862 from the 1,776,131 total burden hours in the ICR approved by OMB under OMB Control No. 2070-0148.  The increase in burden is due to both program changes and adjustments made in assumptions and data used to calculate the time and frequency of required information exchange.  The program changes include modifications to restrictions in field entry activities during restricted entry intervals; increased hazard communications; increased training (for both workers and handlers); increased posting of pesticide application information; provisions for information during emergency assistance; recordkeeping for respirator requirements and for workers performing early entry activities.  Adjustments from the previous ICR are also made where appropriate, due to better information available on the number of respondents and updated wage rates.

The estimated burden represents the total to comply with the full WPS, including all proposed revisions and those that are unchanged by this proposal. This differs from the estimated incremental cost of the proposal, which only considers the net cost of the proposed revisions.

Respondent records are not required to be submitted to the Agency. They are to be retained on the establishment and accessible for inspection.

There is no change in the level of the Agency's burden because neither the existing nor proposed rule imposes any requirements on the Agency.

Accounting Statement

Rule Title: Agricultural Worker Protection Standard Revisions
                                   Category
                               Primary Estimate
                               Minimum Estimate
                               Maximum Estimate
                                    Source
BENEFITS
Monetized Benefits

   * Monetized Benefits from Avoided acute pesticide incidents
                            $5  -  14 million/year
                               $1.2 million/year
                               $28 million/year
EA Chapter 6.5
   * Qualitative Benefits
   *  Willingness to pay to avoid acute effects of pesticide exposure beyond cost of treatment and loss of productivity.
   *  Reduced latent effect of avoided acute pesticide exposure.
   *  Reduced chronic effects from lower chronic pesticide exposure to workers, handlers, and farmworker families.
EA Chapter 6
   * Break-even analysis of the reduced effects of chronic pesticide exposure
   *  Annual chronic benefits necessary to break-even $61.5 million.
   *  Annual risk reduction needed to achieve break-even point: less than 0.8% among farmworkers.
   *  Annual break-even WTP per farmworker: less than $28.
EA Chapter 6.8
COSTS
Monetized Costs
   *  $546  -  640 million over 10 years at 3% discount rate
   *  $62  -  73 million/year
                               $39 million/year
                               $75 million/year
EA Chapter 5.2
Quantified Costs

Qualitative Costs

TRANSFERS
                                     none

                                   Category
                                    Effects
                                    Source
State, local, and/or tribal governments
None.  State and tribal governments responsible for enforcement but revisions will not change level of effort.

Small business
No significant impact on a substantial number of small entities.
    * The rule will affect over 200,000 small farms, nurseries, and greenhouses and several hundred small commercial entities that are contracted to apply pesticides.
    * Impact less than 0.1% of the annual value of sales or revenues for the average small entity.  Highest anticipated impact less than 1% of annual sales.
EA Chapter 5.4
Impact on Jobs
The rule will have a negligible effect on jobs and employment.
   * The marginal cost of a typical farmworker is expected to increase $5/year.
   * The marginal cost for a more skilled pesticide handler is expected to increase by $60, but this is about 0.25 percent of the cost of a part-time employee.
EA Chapter 5.3

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