September 9, 2002

Public Information and Records Integrity Branch
Information Resources and Services Division (7502C),
Office of Pesticide Programs
Environmental Protection Agency
1200 Pennsylvania Avenue, NW
Washington, DC 20460

Re. Docket Control Number: OPP-2002-0110
Revised Organophosphate Cumulative Risk Assessment

Dear Madam/Sir:

Thank you for the opportunity to comment on the Environmental Protection Agency's (EPA) Revised Organophosphate (OP) Cumulative Risk Assessment. I am submitting these comments on behalf of Beyond Pesticides/National Coalition Against the Misuse of Pesticides (Beyond Pesticides), a national membership organization that promotes protection from pesticide hazards and less reliance on chemical dependent pest management.

The passage of the Food Quality Protection Act of 1996 (FQPA) ushered in a new set of responsibilities for the Environmental Protection Agency (EPA). One of the most important of those new responsibilities is the requirement that EPA assess the risks associated with exposure to multiple chemicals from multiple pathways. The Revised OP Cumulative Risk Assessment is a significant first step towards that goal. However, a review of the Revised OP Cumulative Risk Assessment reveals four major flaws:

  • EPA does not have adequate data to lower the 10X FQPA safety factor to the 3X and 1X safety factors assigned in the report;
  • The risk assessment is incomplete, several OP uses were ignored or underestimated;
  • The farmworker community is not adequately protected;
  • EPA must examine the cumulative risk posed by all pesticides and other synthetic chemicals.

Beyond Pesticides' review of the Revised OP Cumulative Risk Assessment, along with numerous scientific studies showing the dangers of organophosphates and organophosphate poisoning incidents reported to our office, leads us to recommend that EPA reinstate the 10X FQPA safety factor and take immediate steps to provide the same level of protection to farmworkers and their families as it does to the general public. Considering farmworker children to be a special identifiable subpopulation under FQPA is key to achieving this goal.

EPA does not have adequate data to lower the 10X FQPA safety factor.

EPA does not have adequate data to abandon the 10X safety factor assigned by the Food Quality Protection Act (FQPA) to protect infants and children. Beyond Pesticides disagrees with EPA's decision to abandon the 10X safety factor in favor of a 3X safety factor. According to the risk assessment, EPA made this decision in cases where animal studies have indicated that younger rats are no more sensitive than adult rats to acetylcholine esterase (AchE) inhibition by repeated exposure to OPs. Beyond Pesticides finds several flaws in this logic. The Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) Scientific Advisory Panel (SAP), established in 1975 to provide scientific advice on pesticides and pesticide related issues as to the impact on health and the environment, has the same concerns concerns. SAP was formed to advise EPA, and the agency must consider the panel's recommendation and reinstate the 10X safety factor.

According to SAP, the were several deficiencies in EPA's cumulative risk analysis including:

1. Extrapolation from data on a limited set of compounds - EPA 's proposal to use a 3-fold factor for the cumulative risk assessment is based on relative sensitivity to cholinesterase inhibition from a set of six organophosphorus toxicants. At most, an approximate 3-fold difference in sensitivity to cholinesterase inhibition was noted in younger animals following repeated dosing. EPA considered that this subset of compounds represents the range of variability of differential responses for all 30 compounds under consideration. The age-dependence of differences in sensitivity to cholinesterase inhibition by the other 24 OP toxicants is unknown. This data gap alone was felt to make it prudent to accept the 10x default.

2. Uncertainties about the mechanisms of age-dependent sensitivity in young rats and their applicability to human beings - Even with the six compounds known to have relatively small age-dependent sensitivity in young rats, the extrapolation to humans is problematic. First, the mechanism of age-dependent sensitivity in rats has not yet been fully elucidated. More important, we lack comprehensive information about the relative biotransformation capacities for OPs in young and adult humans, and about the relative rates of enzyme recovery by de novo synthesis and other mechanisms. Without detailed information of this sort (admittedly difficult to obtain) we cannot be sure that the relatively rapid decrease in OP sensitivity in weanling rats will also apply to children in the critical 1-2 year age group.

3. Limitations of animal models to identify effects of cholinesterase inhibition in children - While EPA noted that the OP cumulative risk assessment is based on AChE inhibition and cholinergic toxicity, more relevant indications of whether an exposure to OPs are "safe for children" are needed, specifically behavioral and cognitive measures such as IQ, attention, language function, etc. Much uncertainty is introduced by using AChE inhibition as a surrogate for these endpoints. For example, as was pointed out at the meeting, it is not known whether a given level of AChE inhibition has the same consequences for a young child as for an adult. Information is largely lacking about the sensitivity, specificity and predictive power of AChE inhibition as a marker for neurobehavioral effects of OPs based on current animal models. In addition, such information is also lacking in terms of high quality epidemiological studies of exposure to pesticides to infants and children. Particularly, the lack of long-term neurobehavioral studies at any stage of development creates a great deal on uncertainty in trying to identify the risks of the OPs to children.

4. Uncertainties about the potential frequency of "high-level exposure " - Another consideration in the application of the FQPA safety factor is confidence in the extent to which the exposure assessment truly captures high-end exposures, particularly in children. Although the Agency proposes to consider upper percentile estimates of exposure in the cumulative risk assessment, these estimates may not be as high as the percentiles imply. As evidence for this, an example was cited in which consumption of small amounts of a single food item (e.g., apple or pear) containing a single OP at the upper end of its PDP range could result in exposure above the 95th percentile for cumulative dietary exposure calculated by the Agency. In view of this, an argument could be made for an additional FQPA safety factor if the benchmark for risk management decision is a percentile of exposure that does not adequately address infrequent, but not truly rare, exposure events.

The Revised OP Cumulative Risk Assessment is incomplete.

EPA's Revised OP Cumulative Risk Assessment ignores several OP uses and completely omits 9 OPs. Beyond Pesticides believes this is both incomplete and deceiving to the public. The public should be able to trust the information released by its government agencies. In the risk assessment EPA paints a very positive picture for the public, suggesting the public has little to worry about. "This scientific assessment of OP pesticide food safety contains good news for American consumers. After years of rigorous scientific work, it strongly supports our confidence that the United States has one of the safest food supplies in the world." By ignoring uses and chemicals in its analysis, EPA is promoting a false sense of security.

Below are examples of organophosphate uses that may be of sufficient dose or frequency to post health risks, but were not included in the Revised Risk Assessment. These omissions render the report incomplete.

1. Use on golf courses - While many uses of the OP chlorpyrifos were agreed to be phased out in June 2000, use on golf courses was allowed to continue because this is a use that, according to EPA, "children will not be exposed." The National Golf Foundation, however, reported that in 2000 children ages 12-17 played 33.8 million rounds of golf, an increase of 15% since 1998. Beyond Pesticides believes that this use should be withdrawn and the cumulative risk assessment should be recalculated.

2. Public health uses - While it is important to protect public health, it is inappropriate to simply ignore pesticide exposure when a product is used as a tool against public health threats. Any exposure is significant to a cumulative risk assessment regardless of the purpose of the application. EPA ignores several public health uses in the Revised OP Cumulative Risk Assessment. These include: naled (black fly control), phosmet (fire ant mound treatment), chlorpyrifos (black fly control and fire ant mound treatment), and temephos (all registered uses).

3. No detectable residues on food - EPA excludes specific OPs from the revised risk assessment if no residues were detected after foods are washed and inedible portions removed. These methods ignore and/or underestimate exposure prior to washing; exposure to farmworkers and their children; exposure at storage, processing and shipping facilities; exposure at farmers markets, farm stands and U-pik farming operations; and exposure to produce grown in home gardens. Tolerances excluded from the Revised OP Cumulative Risk Assessment because no residues were detected: cadusafos (1 tolerance on import bananas), fenitrothion (1 tolerance on wheat gluten), temephos (used as a mosquito larvicide), propetamphos (2 tolerances, for animal feed and for processed food), coumaphos (16 tolerances on meat, meat-by-products, and section 18 honeybee exemptions).

4. Voluntary cancellations and phase-outs - If a manufacturer voluntarily agrees to phase-out a pesticide product or use, EPA does not include it in the revised risk assessment, even if the product remains on the market or legal to use for years to come. Beyond Pesticides is concerned that the phase-out periods may be extended, thus extending exposure to excluded OPs. In addition, private stocks will likely be used regardless of the phase-out agreement. Even if all affected parties strictly follow manufacturer agreements, many uses omitted from the revised risk assessment will continue for years to come. To illustrate this point, the following are examples of chlorpyrifos uses still legal under the manufacturers agreement with EPA. These uses were ignored in the revised risk assessment: all home and garden uses with stockpiled "old label" product purchased before 2002 (may continue indefinitely); spot and local termite use (may continue until December 31, 2002); pre-construction termite use (may continue until December 31, 2005); use in containerized baits (may continue indefinitely); golf course use (may continue indefinitely); and public health applications for mosquitoes and fire ants (may continue indefinitely).

5. Shift in use to other OPs - One may argue that OP uses undergoing phase-out will be illegal in the months and years to come. However, these uses will likely be replaced by other OPs. The increased use of replacement OPs was not accounted for in the revised risk assessment. For example, EPA uses data from the early 1990's to quantify how much trichlorfon is used on lawns (specifically, it used its 1992 Home and Garden Pesticide Use Survey). At that time, diazinon was by far the biggest OP used on lawns. Now that it is gone, only two OPs remain on the market for lawns - trichlorfon, which is available nationally, and bensulide, which may be permitted regional use. EPA did not account for the near certain increase in these chemicals.

The farmworker community is not adequately protected.

Farmworkers, as a group, suffer the highest risks due to their frequency of contact with pesticides. OPs are the group of pesticides that cause the most reported farmworker poisonings each year. EPA has a duty to fashion its policy on pesticides based on the subset of the population that is most susceptible to harm from exposure to pesticides. Farmworkers clearly represent one of the most important groups that must be protected from higher levels of exposure to OPs. Overexposure to these insecticides can cause injury to the brain and nervous system and result in symptoms ranging from nausea, dizziness, and headaches to coma, convulsions and death.

1. Farmworkers receive unequal treatment. Following the mandate of FQPA, the EPA has been conducting new risk assessments of the 39 active ingredients in this group. These reviews have led the EPA to eliminate or phase out use of the most toxic OP products for home and garden purposes. By contrast, only a modest reduction in agricultural uses has been ordered, leaving many highly toxic uses in place. Farmworkers are a subset of the population that is repeatedly ignored when pesticide impacts are evaluated. The Revised OP Risk Assessment is no exception.

Comparing the EPA's recent decisions on some of the most toxic OP insecticides illustrates the very different standard by which farmworker health is judged compared with the health of the general public. With regard to diazinon and chlorpyrifos, for example, the Agency was able to reach an agreement with the pesticide manufacturers to ban or phase out most home and garden uses. By contrast, EPA has allowed many agricultural uses of these chemicals to continue, even though a number of them pose unacceptable risks to workers. In one of its most egregious FIFRA decisions, the EPA has recently granted a four-year renewable registration for the insecticide azinphos-methyl for use on apples, pears and a half dozen other crops, even though the risks to workers from this highly dangerous chemical could not be eliminated. The azinphos-methyl decision is one of the rare instances in which the EPA has explicitly found that the use of an extremely hazardous product could continue on the grounds that the benefits of its use outweigh the risks. The EPA's decision in this instance is highly questionable because many alternative methods exist to replace the use of azinphos-methyl on apples and pears. One such alternative is the use of pheromone mating disruption, which is not at all toxic to people.

2. Farmworker children to be a special identifiable subpopulation whose exposures should be considered under the FQPA standard. Advocates have tried to convince the EPA to designate farmworker children as a vulnerable population, in order to gain some of the benefit of the FQPA standards for the farmworker community. However, a petition requesting that designation has languished. Nor has the EPA been willing to consider drift from treated fields onto nearby homes when aggregating the public's non-occupational exposures for FQPA purposes. The children of farmers, farmworkers and agricultural communities, including over 500,000 children under the age of six, face the greatest risks from exposure due to their small size and higher metabolisms. Farm children should be deemed to comprise an especially vulnerable population, and their exposure to pesticides must be considered in establishing tolerances where data are available. Children who live on or near farms are at risk from airborne pesticide drift when they spend any time outdoors. Pesticides sprayed outdoors may enter houses and concentrate in indoor air. Protection of children necessitates routine, consistent monitoring of ambient air pesticide levels in agricultural regions. In this risk assessment, EPA failed to consider available information concerning the sensitivities and exposures of this major identifiable subgroup of consumers.

These children come in contact with pesticides through residues from their parents' clothing, dust tracked into their homes, contaminated soil in areas where they play, food brought directly from the fields to the table, and contaminated well water. These children are likely to have the highest exposure to pesticides of any group of people in the country. Furthermore, farm children often accompany their parents to work in the fields, raising their pesticide exposures even higher.

At the SAP meeting several members stated that the failure of the risk assessment to address agriculture communities as especially vulnerable to high pesticide exposure is a very serious oversight. Consideration of these communities would include populations that live near agriculture areas, farm families, and effects of spray drift. In addition, one SAP member pointed out that considering protective clothing should also include a consideration of what happens to the clothing after the pesticide application. Does it sit on household furniture; does it sit in a laundry room, or hang in a back porch? These scenarios are real possibilities, particularly in agricultural communities, and are not included in the risk assessment. This leads to an underestimate of the exposure of farm families.

The dangers to the unborn fetus of pregnant farmworker women should also be evaluated under the FQPA standard.

EPA must examine the cumulative risk posed by all pesticides

Despite the flaws mentioned above, Beyond Pesticides applauds EPA for evaluating the cumulative risk of pesticides as required by EPA. However, there are shortcomings in the standards EPA uses for evaluating cumulative risk. EPA should evaluate the common toxic effect of a group of pesticides and other substances, and not use common mechanisms of toxicity as a filter to decrease the number of chemicals it considers in a given Cumulative Assessment Group (CAG). EPA must make a paradigm shift and look at numerous endpoints and the interaction between those endpoints when assessing cumulative risk. The universe of chemicals that is included in the definition of "other substances" along with pesticides must be broad. And, finally, EPA must assume that exposure to pesticides and other substances are at tolerance.

1. Common toxic effect. EPA has completed the Revised OP Cumulative Risk Assessment because it fits the criteria of a CAG. The current Guidance on Cumulative Risk requires that chemicals share both a common toxic effect and a common mechanism of toxicity to be considered in a CAG. This system is flawed. In the real world, a liver cannot tell the difference between two cancer causing chemicals because of the biochemical route each chemical takes to cause that cancer. In other words, if a number of pesticides and other substances cause liver cancer via a number of different pathways the end result is the same, a diseased liver. EPA should not use common mechanisms of toxicity as a filter to decrease the number of chemicals it considers in a given CAG.

An important example is the cumulative exposure to the OPs and carbamates. Both of these families of chemicals have been shown to inhibit acetylcholine (ACh) function. Although these two sets of pesticides inhibit ACh in different ways, the effect is the same, a body exposed to both an OP and a carbamate would experience inhibition of ACh as the result of the cumulative effect of exposure to these pesticides. EPA must think "outside the box" and develop a protocol that will consider these types of cumulative effects.

2. Interactions Between Multiple Endpoints. The development of a protocol for cumulative risk assessment calls for a paradigm shift on the part of EPA in order to calculate the real world risks to people exposed to multiple pesticides via multiple pathways. The current system follows EPA's standard procedure of selecting endpoints and considering them in isolation from other toxic effects. Different endpoints have been shown to influence one another. For example, if a chemical causes a suppression of the immune system this could cause an increase in the risk of cancer. Historically, EPA has assessed the risks associated with one chemical at a time, focusing on a small number of endpoints, without consideration of either exposure to additional toxins or the interaction between endpoints. FQPA requires EPA to consider the cumulative effect of exposure to multiple chemicals EPA should also move to consider the effects of interactions of multiple endpoints. Looking at each endpoint individually ignores the complicated set of interactions that occur within a body exposed to a variety of toxic chemicals. There are a huge number of variables in the real world. EPA must recognize this fact and exercise its authority to protect human health through the reduction of exposure to pesticides and other substances.

3. Exposure to Pesticides and "Other Substances." People are exposed to a large number of environmental toxins as they go about their lives. In order for EPA to accurately assess the risks of exposure to multiple pesticides the agency must factor in as wide a range of pesticides and other substances as possible. The agency must include in its definition of "other substances" the inert ingredients in pesticide formulations as well as all contaminants and metabolites of pesticides. It is also very important that EPA factor in the effects of those pharmaceuticals that have toxic effects in common with pesticides. It is also important that EPA factor in environmental contaminants such as dioxins, PCBs and other byproducts of the chemical industry when assessing cumulative risk.

4. Assume Exposure at Tolerance. EPA has stated that it will not consider the worst-case scenario in its calculation of cumulative risk. The agency's "hypothetical person" must include a worst-case scenario because it encompasses the widest range of people, i.e. if the worst case is protected then we all are protected. There are also important environmental justice issues associated with consideration of a worst-case scenario.

Pesticide Poisoning Incidents

Risk assessment is not simply a set of numbers on a page. First and foremost, EPA must keep in mind that its policy affects real people, people whose health has been negatively impacted as a result of exposure to pesticides and other substances. Beyond Pesticides is regularly contacted by people who have been exposed to pesticides. They share their stories with us through our Pesticide Incident Reporting program.

Mary Jane, Lawrence and Kaitlyn Hannan, Greenwood, Indiana, were exposed to the organophosphate insecticides chlorpyrifos (Dursban) and diazinon (Knox Out) following a treatment for ant control in 1993. Upon reentering the house a few hours after the application, as advised by pest management company, parents Mary Jane and Lawrence and their daughter Kaitlyn experienced flu-like symptoms (headache, sore throat, nausea, dizziness, nasal congestion, chest tightness, diarrhea, burning eyes, weakness, cough and nasal drainage), all consistent with the symptoms of organophosphate poisoning. The symptoms worsened in the house and improved in fresh air. The Hannans were forced to vacate their home. Because it is contaminated with organophosphates, the home cannot be sold.

John Boldman of Carpentersville, Illinois was exposed to chlorpyrifos, in combination with other pesticides, while working in a greenhouse. As a result of his exposure to these pesticides, he ended up in the emergency room of the local hospital. Mr. Boldman continues to have difficulty breathing, flu-like symptoms, arthritis, numbness in hands and legs, body aches, muscle twitches, and feelings of confusion. He has become extremely sensitive to chemicals, even at levels undetectable to the average person.

Alex and Christina Ebling of New Albany, Indiana, ages 4 and 7, were exposed to diazinon, chlorpyrifos, pyrethrins and piperonyl butoxide in 1997. The brother and sister were exposed in their home following an application with a fan spray. A professional applicator and maintenance personnel at their apartment complex applied the pesticides for home insect pests. The apartment applied the pesticides from 1994 through 1997 as a preventative measure. Although pests never bothered them, the children now suffer from respiratory problems and seizures.


Our analysis of the Revised OP Cumulative Risk Assessment reveals that EPA has intentionally excluded and underestimated the risk of many OP uses, which provide significant routes of exposure. Until all known uses of OPs are included the report is incomplete and EPA must reinstate the 10X FQPA Safety Standard. Most notably, the risk assessment incorporates industry phase-out agreements as if they impact present OP residue levels. Obviously, many of these changes will take years before they have any real impact, and some will never have an impact (for example, labeling recommendations which are not followed). Moreover, although the Agency takes full credit for discounting OP residue levels based on future mitigation effects, it does not incorporate in any way the obvious risk-trading effects that will occur. That is, as the most toxic OPs are removed from the market, other OPs will increase in use, to replace them. This is not acknowledged in any way in the Revised OP Cumulative Risk Assessment.

EPA must also provide the same level of protection to farmworkers and their families as it does to the general public. EPA should consider farmworker children to be a special identifiable subpopulation whose exposures should be considered under the FQPA standard. The dangers to the unborn fetus of pregnant farmworker women should also be evaluated under the FQPA standard. Again, EPA should apply the 10x FQPA Safety Standard.


John Kepner
Beyond Pesticides