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October 16, 2000

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-34203C

Dear Madam/Sir:

Thank you for the opportunity to comment on both the risk mitigation measures that are part of the Environmental Protection Agency’s (EPA) agreement with the registrants of chlorpyrifos and the revised risk assessment for occupational exposure. I am submitting these comments on behalf of Beyond Pesticides/National Coalition Against the Misuse of Pesticides (Beyond Pesticides).

A review of the revised risk assessment of chlorpyrifos reveals numerous data gaps, a failure on the part of the Environmental Protection Agency (EPA) to fully assess aggregate risks, as well as extreme health risks from both occupational and non-occupational exposure to this pesticide. Given the information that the agency does have on chlorpyrifos the EPA should take immediate steps to file a final determination and notice of intent to cancel and deny application for reregistration of pesticide products containing chlorpyrifos.

The phase-out agreement that EPA reached with the registrants on chlorpyrifos does not go far enough to protect human health and the environment. EPA has chosen to take action to restrict the uses of chlorpyrifos because of the extreme risk that exposure to chlorpyrifos poses to workers, homeowners and children. EPA needs to exercise its authority based on those risks to cancel uses of chlorpyrifos immediately, instead of allowing a phase-out of uses with the inevitable exposure linked to the continued use.

EPA should also take steps to immediately restrict uses of chlorpyrifos that lead to occupational exposure. The Agricultural and Occupational Exposure Assessment for chlorpyrifos states that 30.3% of occupational scenarios exceed the agency’s level of concern, even with maximum personal protective equipment (PPE) and engineering controls for handlers. In fact, two of the occupational exposure scenarios have MOEs less than 10.[1] EPA must act on both the known risk of illness to workers from exposure to chlorpyrifos and the numerous data gaps identified by the agency and cancel uses of this pesticide.

EPA’s Agreement with Registrants of Chlorpyrifos

On June 8, 2000, EPA announced an agreement it had reached with Dow AgroSciences which phases out most home uses of the commonly used insecticide, but allows sales to continue through 2001 and all existing stocks to be used by the general public and sold by pest control companies for as long as they last.[2] This announcement spurred New York State Attorney General Eliot Spitzer into action, calling on retailers in his state to stop the sale of chlorpyrifos immediately.[3]

EPA’s chlorpyrifos announcement begins the process of getting high consumer and children exposure uses of chlorpyrifos off the market, but puts people at risk by not stopping its use immediately. The decision allows for an 18-month phase-out of sales of deleted uses, and a lengthy period, probably years, during which pest control companies and other applicators can use up existing stocks of the chemical. Beyond Pesticides has expressed concern about the extraordinarily high risks associated with use during the phase-out period, some that exceed EPA levels of concern by over 100 times. Two, of the many, extreme examples of risk that will continue during the phase out of chlorpyrifos include a Margin of Exposure (MOE) of 6 for children exposed to dursban turf insecticide, and a MOE of 84 for children living in houses treated for termites, post construction.[4] It is important to note that EPA has determined a MOE of 1000 or greater is necessary to satisfy its level of concern.

In a letter to major retailers, Mr. Spitzer said the voluntary pullback agreed to by EPA and chemical manufacturers does not go far enough in protecting children and pets. "The danger from this product is clear," Mr. Spitzer said in the letter to Wal-Mart, Home Depot, Ace Hardware and other stores. "We must do more to prevent exposure to this dangerous chemical" by yanking products with chlorpyrifos off the shelves immediately.[5]

EPA negotiations with Dow allow for continued uses that will certainly cause exposure (although application rates are being reduced through a phase-out process, allowing for old label stocks to be used up) to those who play golf or live near golf courses, live in communities with mosquito spray programs, or utilize indoor spaces that use containerized baits for cockroach control.

EPA’s rationale for allowing continued use on golf courses is particularly troubling. EPA’s Office of Prevention, Pesticides and Toxic Substances (OPPTS) published Chlorpyrifos Revised Risk Assessment and Agreement with
Registrants, in June of 2000. That document includes a table outlining the provisions of the agreement and associated EPA actions. The table lists non-agricultural uses that will remain, including outdoor areas where children will not be exposed such as golf courses. Anyone even mildly interested in the world of sports knows that the popularity of golf among young people has skyrocketed in the last few years. The latest statistics from the National Golf Foundation states that since 1986, the number of junior golfers has increased 43% to 2 million.[6] EPA cannot assume that children will not be exposed to chlorpyrifos used on golf courses. Given the extreme risk to children exposed to Dursban applied to turf (see the example above, MOE of 6 for children exposed to Dursban turf insecticide) EPA must take immediate steps to cancel the use of chlorpyrifos on golf courses.

The phase out of chlorpyrifos as a termite insecticide for new residential construction treatment will not take effect until the end of 2005. Nor will the prohibition on production kick in until the end of 2004. According to Dow, "This date may be extended, however, based on the results of an exposure study specific to this application."[7] At this point, Dow has not submitted to EPA any plan for conducting such a study, which presumably would involve human subjects living in new homes that had been treated pre-construction for termites. "Spot and local" treatment of existing buildings will not stop until the end of 2002.

EPA is required to calculate the "aggregate" risks of exposure to pesticides under the Food Quality Protection Act. According to agency documents, the full risk of continued exposure during the phase-out and use of existing stocks has not been calculated. EPA writes, "Aggregate risk is defined as the combined risk from exposure through food, drinking water, and residential uses." It continues, "The short-term and intermediate-term aggregate risks were not originally calculated for chlorpyrifos because the risks from residential exposure alone exceeded the Agency's level of concern based on currently registered uses.[8] The same is said for long-term aggregate risk.

In effect, EPA is saying that it has not calculated the aggregate risks associated with continued exposure to chlorpyrifos during the period of phase-out and use of existing stocks. Given how high the individual exposure risks are for some uses of chlorpyrifos, it is likely that combined or aggregate exposures (i.e. lawn care, indoor use and food) during the time period of continued exposure qualifies chlorpyrifos, with EPA's own numbers, for a faster removal from the market, utilizing the "imminent hazard" provisions for pesticide suspension. Beyond Pesticides believes that EPA has a duty to at least make the calculation before negotiating the public's health.

Agricultural and Occupational Exposure

EPA’s revised agriculture and occupational exposure assessment cites numerous data gaps and points out extreme health risks to workers exposed to chlorpyrifos. In addition, EPA has adopted throughout the risk assessment the notion that risk concerns below the acceptable level with baseline protections can be moderated by mitigation techniques, such as personal protective equipment (PPE). Much of the risk mitigation that EPA suggests is not evaluated for efficacy or usability. EPA does not assess the degree to which it can enforce use of PPEs and therefore ensure that the exposure assumptions in its risk assessment are valid. Similarly with agricultural use, since the label rate is the enforcement level, EPA must assume in all cases that applications to food crops and other uses will occur at maximum label rates, otherwise the agency has no basis for protecting people who are exposed above the rate assumed in the risk assessment. If EPA cannot enforce under law the levels of exposure that it utilizes in its risk assessments, then it should not be using those exposure assumptions in its risk assessment.

Agricultural Uses

Chlorpyrifos is currently registered for use on a large number of agricultural products including: cranberries, strawberries, citrus, apples, figs, pears, nectarines, cherries, peaches, plums, grapes, almonds, pecans, walnuts, onions, peppers, kale, broccoli, brussels sproats, cabbage, cauliflower, collards, cucurbits, asparagus, roots/tubers, corn, tomatoes, lentils, beans, peas, sorghum, tobacco, wheat, alfalfa, peanuts, soybeans, sunflower, cotton, sugar beets, mint, bananas, pasture, woodland, and lots/farmsteads.[9] It is important to note the large number of crops and sites on which chlorpyrifos can be used. Only two registered uses of chlorpyrifos are effected by EPA’s current action, tomatoes and pre-bloom applications on apples.

The vast majority of agricultural uses are unaffected by the agency’s proposed action. Farmworkers, as a group, suffer the highest risks due to their frequency of contact with pesticides. 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 chlorpyrifos.

EPA calculated MOEs for 18 agricultural uses of chlorpyrifos, the agency lists three additional agricultural exposure scenarios for which it had no data: seed treatment, dip application (preplant peaches) and dry bulk fertilizer impregnation.[10] Of those 18 agricultural uses, 15 (83.3%) have MOEs that exceed the agency’s level of concern using maximum PPE. Two scenarios are particularly worthy of note because of the extreme risks associated with that use: aerial (granulars), applied from an enclosed cockpit, MOE of 8; and, hydraulic hand held sprayer for bark/pine seedling treatment, with an total MOE of 6.

Postapplication exposures also represent a significant risk to farmworkers. EPA has determined that scouts, wet pruners, dry pruners and harvesters all face elevated risk from entering fields treated with chlorpyrifos. This is true for both short-term and intermediate-term risks. Some of the most extreme examples calculated by EPA include those for short-term exposure faced by citrus workers. EPA determined that scouts (MOE=46), wet pruners (MOE=14), dry pruners (MOE=34), and harvesters (MOE=7) are at risk from working in treated orchards.[11]

Intermediate-term exposure faced by farmworkers in fields treated with chlorpyrifos also exceeds the agency’s level of concern. For example, EPA has assigned a MOE of 73 for harvesters of cauliflower.

Children of farmworkers face the greatest risks from exposure due to their small size and higher metabolisms.[12] One of the most significant data gaps in the revised chlorpyrifos risk assessment is that EPA does not have “Methodologies to estimate dermal and/or incidental oral exposure from crop residues for younger children accompanying adults into treated fields are not available at this time.”[13] The Health Effects Division (HED) found that adults “playing” on treated lawns exceed HED’s level of concern. “HED has the same type of concerns that children under 12 years old that venture into treated fields may not be sufficiently protected at the estimated REIs.”[14]

EPA cannot enter into policy agreements and negotiate the public’s health with the data gaps described above. It is unacceptable to continue to allow workers and their children to be exposed to this level of risk that EPA can currently calculate. If those exceedingly small MOEs do not meet the definition of “imminent hazard” under FIFRA, requiring an immediate suspension of registration, then arguably EPA has not established a legitimate standard for that legal term.

Non-agricultural Uses

EPA’s recent agreement with the registrants of chlorpyrifos will eventually have an impact on the level of exposure faced by non-agricultural occupations. As described above, our concern stems from the delayed cancellation of chlorpyrifos that is the phase-out agreement. EPA cites numerous data gaps in its revised occupational/residential handler assessment for chlorpyrifos. For example, HED is in the process of revising the residential exposure assessment Standard Operating Procedures (SOPs). According to the agency, “some of the secondary exposure pathways that EPA will be addressing include exposures resulting from residue tracked into homes from outdoor use, indoor dust, and spray drift.”[15] The recent study cited by EPA in which polycyclic aromatic hydrocarbons (PAHs) that are abundant in house dust were shown to increase the toxicity of chlorpyrifos in vitro, particularly at low levels (i.e., 2-50 FM PAHs with 1-180 nM chlorpyrifos-oxon, a metabolite of chlorpyrifos that inhibits acetyl cholinesterase).[16] It is negligent at best for EPA to enter into a phase-out agreement with the registrant of chlorpyrifos and negotiate the health of children without information regarding these residues.

EPA cites additional gaps in data, including a long list of chlorpyrifos uses that would lead to certain exposure to the public. That list includes: use in vehicles (i.e., planes, trains, automobiles, buses, boats); and other current label uses such as treatment of indoor exposed wood surfaces, supermarkets, restaurants, theaters, playhouses, furniture, and draperies, etc.[17]

EPA looked at 23 occupational exposure scenarios. Of those 23, 22 (95.6%) scenarios had MOEs that exceed the agency’s level of concern. It is not only the high percentage of occupational scenarios with unacceptable risks that is of concern. The MOEs for a number of the scenarios are exceedingly small. One example, intermediate-term risk faced by applicators of ant killer, indicates that workers are always being exposed on the job to doses of chlorpyrifos that are greater than the LOAEL. These workers have been assigned an MOE of 0.8.[18] In other words, those workers are always exposed to enough diazinon to adversely effect their health.


Our analysis of the revised risk assessment for chlorpyrifos reveals that EPA is aware of many data gaps and the exceptionally high risks to the environment, workers homeowners and particularly children. Based on the EPA’s own analysis, continued use of chlorpyrifos represents an imminent hazard to the health of people and the environment and as such EPA must act to remove all uses of chlorpyrifos from the market immediately.

The phase-out agreement that EPA entered with the registrants of chlorpyrifos does not go nearly far enough to protect the public health. EPA must consider the many data gaps and the extremely low MOEs faced by people exposed to chlorpyrifos before it can negotiate with chemical manufacturers in the name of protecting the public health.


Gregory S. Kidd
Science and Legal Policy Director

[1] EPA, OPPST, Agricultural and Occupational Exposure Assessment for the Reregistration Eligibility Decision for Chlorpyrifos, p. 5. June 19, 2000.

[2] U.S. Environmental Protection Agency, Prevention, pesticides and Toxic Substances, Chlorpyrifos Revised Risk Assessment and Agreement with Registrants, Washington, DC, June 2000.

[3] The Honorable Eliot Spitzer, Attorney General, State of New York, Albany, NY, letter to Arthur M. Blank,
President/CEO, Home Depot, Inc., June 8, 2000.

[4] See, tables 3, page 71 and A-1, page 80 in U.S. EPA, Occupational/Residential Handler and Postapplication
Residential/Non-Occupational Risk Assessment for Chlorpyrifos. DP Barcode: D266562.

[5] Spitzer, June 8, 2000.

[6] From: Excerpts from Trends in the Golf Industry 1986-1999. Available on the National Golf Foundation website,

[7] Heather Woolford, Dow AgroSciences, Press Release, Dow AgroSciences Announces Changes in Use of Chlorpyrifos Products, June 8, 2000.

[8] U.S. Environmental Protection Agency, Overview of Chlorpyrifos Revised Risk Assessment, June 8, 2000., p.18.

[9] EPA, Overview, June 8, 2000, p. 1-2.

[10] EPA, Agricultural and Occupational Exposure Assessment, Table 4, pgs. 35-38.

[11] EPA, Agricultural and Occupational Exposure Assessment, Table B5, p. 75.

[12] National Research Council, National Academy of Sciences, Pesticides in the Diets of Infants and Children,
Washington, DC: National Academy Press, 1993.

[13] EPA, Agricultural and Occupational Exposure Assessment, p. 50.

[14] Ibid.

[15] EPA, Occupational/Residential Handler and Postapplication Residential/Non-Occupational Risk Assessment for
Chlorpyrifos. June 20, 2000. pgs. 6-7.

[16] Jett D.A., Navoa, R.V., Lyons, M.A. 1999. Additive inhibitory action of chlorpyrifos and polycyclic aromatic hydrocarbons on
acetylcholinesterase activity in vitro. Toxicology Letters. 105:223-229.

[17] EPA, Occupational/Residential Handler Risk Assessment, p. 7.

[18] EPA, Occupational/Residential Handler Risk Assessment, Table 2, p. 65.