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July 18, 2000

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

Re. Docket Control Number: OPP-34225

Dear Madam/Sir:

Thank you for the opportunity to comment on the preliminary risk assessment of the Reregistration Eligibility Decision (RED) Document for the organophosphate diazinon (PRA-Diazinon) A RED for diazinon should be issued only if data on diazinon and its contaminants, metabolites and the inert ingredients in its formulations are complete and support reregistration under the standards of authorizing legislation and corresponding regulations. A review of the preliminary risk assessment of diazinon 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 diazinon 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 diazinon.

EPA must use the 10x safety standard under the Food Quality Protection Act

Congress overwhelmingly passed FQPA to address, among other concerns, the particular hazards faced by children from exposure to pesticides. Diazinon is one of the leading causes of acute reactions to insecticide use reported as poisoning incidents in the United States. (PRA-Diazinon p. 7) Much of the frequency of the reported incidents for diazinon is accounted for by the widespread use of this chemical inside and outside the home. (Ibid) Diazinon was the fifth most common pesticide found in U.S. homes in a survey conducted by EPA in 1990. (Ibid) Clearly, diazinon represents a major source of exposure to organophosphate pesticides to young children given its common use in and around homes. This fact alone is enough to preclude EPA from lowering the 10x safety factor for diazinon provided for by FQPA.

EPA has determined that it is appropriate to treat organophosphates (OPs) as sharing a common mechanism of toxicity, namely the inhibition of cholinesterase activity. As required by FQPA, the agency is currently developing a protocol for a cumulative assessment to evaluate the risk from food, water and non-occupational exposure resulting from all uses of OPs. EPA cannot lower the 10x safety factor given the lack of a cumulative risk assessment. This represents a major gap in EPA's database on diazinon specifically and the OPs generally.

In addition, there are a number of important data gaps in the residential risk estimates of diazinon. The 10x safety factor is intended to protect children in the face of incomplete data on the health risks associated with pesticides. The risk assessment states that "given the uncertainty in diazinon concentrations in surface water . . . and, therefore the uncertainty relative to diazinon concentrations in drinking water, HED recommends reassessing the potential acute exposure to diazinon in drinking water once surface water-sourced drinking water monitoring data on diazinon become available for use." (PRA-Diazinon p. 11) HED also recommends "reassessing the potential chronic exposure to diazinon in drinking water once surface-water sourced drinking water monitoring data on diazinon become available for use." (PRA-Diazinon p. 12) The database on diazinon is clearly incomplete for water and precludes EPA from lowering the FQPA safety factor.

According to the risk assessment no chemical specific exposure data were available to estimate handler, or post application dermal and inhalation exposures to diazinon for typical homeowner uses. (PRA-Diazinon p. 12) This is particularly shocking given the widespread use of diazinon in and around homes. Even more shocking is that EPA has neglected to calculate the risks of aggregate exposures (dermal plus inhalation) for residential handlers of diazinon. The stated reason for this is that all short-term dermal exposures and inhalation exposures exceed HED's level of concern for all residential handler exposure scenarios except one. Thus, "aggregating exposures, (dermal plus inhalation), for residential handlers would only result in risk estimates that further exceed HED's level of concern." (Ibid)

This same line of reasoning is applied to aggregating short-term exposures from food, drinking water and residential exposures for handlers; short-term exposures from food and drinking water with postapplication residential exposures from indoor crack and crevice treatments; and, short-term exposures from food and drinking water with postapplication residential exposures from lawn treatments with liquid formulations of diazinon. (PRA-Diazinon p. 114) EPA's failure to calculate the risks associated with these aggregate exposures represent major data gaps that preclude EPA from lowering the FQPA 10x safety factor.

Calculation of aggregate exposure necessary for determination of imminent hazard

EPA must consider the aggregate exposure data to accurately assess whether continued exposure to diazinon represents an "imminent hazard" as defined in the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) § 2(l) in the event that EPA opts to cancel uses of diazinon. EPA must exercise its authority under FIFRA § 6(c)(1) to immediately suspend the registration of a pesticide if the Administrator determines that action is necessary to prevent an imminent hazard during the time required for cancellation proceedings.

EPA failure to evaluate the Aggregate Risk Indices (ARIs) for all uses, including those that exceed HED's level of concern is a violation of FIFRA. In NCAMP v. EPA, United States District Court for the District of Columbia (February 23, 1988), 679 F.Supp. 55 (D.D.C.1988), Judge Louis Oberdorfer ordered in February, 1988 that "commercial use and commercial application of existing stocks of chlordane and heptachlor which have been the subject of voluntary cancellations shall cease." The court found that the agency's decision to permit continued use of the chlordane stocks under a negotiated agreement with Velsicol Chemical Company constituted arbitrary and capricious action. The court further found that, "EPA's policy of exchanging use authorization on existing stocks for voluntary cancellations . . .does not satisfy the agency's obligation under 7 U.S.C. 136(a)(1)."

The EPA cannot fully assess the risks associated with a phase-out of diazinon without having calculated all of the risks associated with residential exposure. It would be unlawful for EPA to allow a phase-out of diazinon, like EPA's recent chlorpyrifos agreement, without first determining whether diazinon represents an imminent threat. Therefore, EPA must calculate all risks associated with aggregated exposures to diazinon.

Based on known hazards of diazinon EPA cannot reach the conclusion that diazinon will not pose an unreasonable risk to humans or the environment

Occupational Exposure and Risk

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 which it utilizes in its risk assessments, then it should not be using those exposure assumptions in its risk assessment.

HED estimated risks for 27 occupational handler scenarios. Risks based on short-term dermal exposure indicate that risks are unacceptable for all of the 26 scenarios (100%) for which there is data, using baseline protection and typical application rates. With maximum PPE all of the 26 scenarios (100%) for which there was data, had unacceptable risks using typical application rates. Only 16 of the 27 occupational scenarios considered could employ the use of engineering controls to provide additional protection for workers. Of those, 13 (81.25%) had unacceptable risks at typical application rates. (PRA-Diazinon p. 78-79, Table 23b)

Risks based on intermediate-term and long-term dermal exposure show the exact same trend. With baseline protections at typical application rates 100% (26) of the scenarios have unacceptable risks. With maximum PPE, 100% (26) of scenarios have unacceptable risks. Of the 16 scenarios that can employ engineering controls, 93.75% (15) have unacceptable risks at typical application rates. (PRA-Diazinon p. 82-83, Table 24b)

Occupational handler inhalation MOEs show the same trend. With baseline protections and at typical application rates, 100% (26) of the scenarios have unacceptable risks. With PPE at typical application rates 84.6% (22) of the scenarios have unacceptable risks. Of the 16 scenarios that can employ engineering controls, 68.75% (11) have unacceptable risks. (PRA-Diazinon p. 89, Table 25b)

Turning to the combined risk estimates for short-term dermal and inhalation exposure reveals that most scenarios have unacceptable risks. Combining the exposure considered with either baseline, PPE or engineering control protections, 7 out of 16 (43.75%) have an Aggregate Risk Index (ARI) less than 1. (PRA-Diazinon p. 92, Table 26)

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, indicating that workers are always being exposed on the job to doses of diazinon that are greater than the NOAEL (in the case of dermal exposure) or the LOAEL (in the case of inhalation exposure) In other words, those workers are always exposed to enough diazinon to adversely effect their health. The most extreme example is high-pressure handwand applicators using typical rates have an MOE of 0.000189. For short-term dermal exposure with baseline protection and typical application rates, 61.5% (16) have MOEs less than 1. With maximum PPE at typical application rates, 26.9% (7) have MOEs less than 1. And even with engineering controls at typical application rates, one of the scenarios has an MOE less than 1.

The situation with intermediate-term and long-term exposure is more dire. With baseline protections and at typical application rates, 88.4% (23) of the scenarios have MOEs less than 1. With maximum PPE at typical application rates 69.2% (18) have MOEs less than 1. With engineering controls at typical application rates, 37.5% (6) have MOEs less than 1.

In making a meaningful determination of risks associated with the use of diazinon, EPA must consider real world situations. MOEs were calculated for short-term and intermediate-term risks based on days after treatment of three crop situations in order to estimate safe reentry intervals (REIs) For tree crops a MOE above 100 was not reached until 25 days after treatment. For grapes a MOE above 100 was not reached until 22 days after treatment. And even for low potential exposure crops it was not until 19 days after treatment that an acceptable MOE was reached. (PRA-Diazinon p. 95, Table 28) HED notes that safe REIs "could not be established for short- and intermediate-term dermal exposures incurred through harvesting activities associated with grapes." (PRA-Diazinon p. 93-94)

It is unacceptable to continue to allow workers to be exposed to this level of risk. 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.

Residential Exposure and Risk Estimates

Diazinon has a wide variety of homeowner uses including lawn treatments, spot treatments, and indoor crack and crevice treatment. This brings children into regular contact with this organophosphate pesticide. EPA fails to evaluate both its assumption that home users of pesticides comply with the label instructions and the inability to enforce non-compliance with label instructions. EPA also fails to include in the risk assessment any consideration of accident scenarios often associated with home use of pesticides, note the large number of incident reports involving non-occupational exposure to diazinon. HED conducted risk assessments for only 7 residential exposure scenarios. The same trend is evident with MOEs with residential exposure as with occupational exposure, the vast majority are unacceptable.

Residential handler MOEs for short-term dermal and inhalation exposure indicates that 100% (7) of the scenarios have unacceptable MOEs for dermal exposure using typical rates of application. The exceedingly small size of the majority of these MOEs, 57% (4) have MOEs less than 1, indicates that many residential uses of diazinon expose homeowners and children to doses above the NOAEL. The inhalation MOEs are equally problematic, with 71.4% (5) having unacceptable MOEs, one of which is less than 1. (PRA-Diazinon p. 101-102, Table 30b)

Turning to the four turf scenarios that were examined, 100% (4) have both unacceptable short-term dermal MOEs and inhalation MOEs. Three of the dermal MOEs are less than 1. (PRA-Diazinon p. 103, Table 30(c)) All of the nonirrigated transferable turf residues for short-term dermal exposure to liquid formulation of diazinon in GA, CA and PA have unacceptable MOEs. (PRA-Diazinon p. 105-106, Table 31(a))

It is the short-term post-application indoor (crack and crevice) inhalation and dermal risk estimates that are most disturbing. Of the four inhalation exposure calculations, including both toddler and adult exposure, 100% (4) have unacceptable MOEs. (PRA-Diazinon p. 110, Table 32(a)) Dermal exposure reveals the same trend. Of the eight dermal exposure sources, with both adults and toddlers, 100% (8) have unacceptable MOEs. For both toddlers and adults the MOEs are less than 1 for 100% of the scenarios. (PRA-Diazinon p. 110-111, Table 32(b))

It is unacceptable to continue to allow children and homeowners to be exposed to this level of risk. 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.

Incident Reports

HED concludes that "majority of the reported incidents of acute reactions to diazinon, reported as 'poisoning incidents,' occur in the home." (PRA-Diazinon p. 111) Beyond Pesticides/NCAMP works with numerous people who believe that diazinon has made them or their family members chronically ill. It is difficult to fully document all the exposure incidents to diazinon because not all exposures are reported to our organization, the manufacturer, EPA or poison control centers, not all exposures are linked to a specific pesticide, and not all health effects are recognized by doctors as being related to pesticides.

Consistently, people who have contacted our organization regarding their exposure to diazinon have reported similar health effects: headaches, coughing, nausea, depression, muscle twitching, confusion, etc. Although these heath effects are considered relatively minor, they are prevalent enough to warrant EPA take action and remove diazinon from the market.

Following are just a few examples of people who have been poisoned by diazinon.

· Russell Alessi of Parlin, New Jersey was exposed to diazinon (SpectracideTM) in 1990. He had an eight-ounce can that was leaking in his storage bin. He took it outside to empty the can of its contents. When he unscrewed the cap, the can exploded spraying the liquid all over his face, neck, arms and body. When this happened he inhaled a great amount of fumes and ingested the pesticide as it was sprayed on his lips and some got in his mouth. As a result of the incident he has a burning sensation in his mouth and on the right side of his tongue, lost the ability to smell and taste, irritated gums, swollen and discolored tongue, headaches, violent dreams, nervousness, and loss of balance.

· Gracie Soliz of San Diego, Texas was exposed to diazinon (SpectracideTM) that was applied to her lawn. Immediately following the application she complained of difficulty breathing, incessant coughing, and itchy skin.

· Gerald Robinson of Philadelphia, Pennsylvania was poisoned by diazinon (Diazinon 4ETM) that was applied to his apartment by the managing agency in 1998. This routine spraying was made with a pump spray bottle to control cockroaches. Gerald was lead to believe that the pesticide was safe. There was a strong persistent odor that remained for several days after the pesticide application. During this time, he inhaled the vapors and ingested residues left on food products. He later saw the full spray bottle on the freight elevator. For the following month he suffered from various health problems associated with the exposure.

· Margaret Martin of Greenwood, Missouri bought a can of diazinon to get rid of her problem with spider mites. Although she stated that she followed the directions on the can for indoor and outdoor use, after she applied the pesticide, she became very ill and was bedridden for months. A few years later, she hired a pest control company to take care of another pest problem she was having, who also used a diazinon product. From the second exposure, she is now permanently disabled and unable to take care of herself.

Following are a few examples of people who have been poisoned by diazinon applied with other pesticides.

· Linda Baker of Fort Scott, Kansas was poisoned by a mix of chemicals including diazinon when she entered her office at the school where she taught in 1997. The fumes instantly overwhelmed her. Over the following week, several school staff members complained of headaches and nausea. The school janitor had sprayed diazinon throughout the inside of the school with an aerosol container in the attempt to control roaches. She was told the pesticide was safe. No prior notification was given to her and no signs were posted in the school stating that the pesticide had been applied. She became chemically sensitized as a result of this particular pesticide poisoning incident. A health care professional has diagnosed her poisoning. This incident ended her 20-year career as an active physical education teacher. She stated that her school's janitors had little training in applying pesticides and that the janitor told her that salesman often left samples of the pesticide and they would just "grab some off the shelves" when they wanted.

· Christina and Alex Ebling, daughter and son of Mr. and Mrs. Ebling of New Albany, Indiana, were exposed to a mix of pesticides including diazinon in their home in 1994. The repeated applications were done by a professional pesticide applicator and maintenance personnel at their apartment complex. Their exposure was dermal and inhalation. Mrs. Ebling stated that the pesticide application was to prevent a pest problem from occurring. The two children developed seizures, learning disabilities and incontinence.

· An attorney representing a gentleman from Savannah, Georgia reported that his client worked for an exterminating company and regularly sprayed diazinon and Talon GTM. During the second year of his job with the company, he began to have severe respiratory problems, headaches, nausea, and bloody diarrhea.

· Cheryl Banister of Chalfont, Pennsylvania was poisoned by diazinon (Diazinon 2DTM), bendiocarb (Ficam WTM), and fenvalerate (ConquerTM) in 1998 while at work. She states that the routine pesticide application was to control insects and mice. The pesticides were applied by a commercial applicator using spot treatments inside her office building. She began showing signs of the exposure immediately. Her symptoms included: diarrhea, coughing, blurry vision, problems wetting her pants, memory loss, depression, anxiety, ear pains, sleeping problems, and hair loss. Her family doctor did not know what test to run or that it could be related to a chemical exposure. She later found a specialist who ran the appropriate medical tests and linked her health problems with exposure to organophosphate pesticides. She continues to have health problems today and is unable to work because of the exposure. She has been denied workman's compensation.

Following are a few examples of people who have been poisoned by diazinon due to its misapplication. This list is significant in that it demonstrates the EPA's inability to ensure label compliance.

· Don and Kathy McLaughlin and their family of Salem, Oregon were poisoned by diazinon (Knox-OutTM) used for fleas in 1989. Mrs. McLaughlin was home with her baby when the hired pest control applicator, and the applicators 17-year-old son who was a trainee, arrived. Mrs. McLaughlin was not ready to leave her home and asked the applicator to start at the other end of the house, which he did. But before she could leave, the applicator moved through the house and began spraying in the nursery where she was with her baby and continued to spray the room while they where there. The applicator told her that it was "completely harmless" and "not to worry." Mrs. McLaughlin got her older daughter to take the baby out to the car. Neither man wore a mask. The trainee was spraying over areas, including chairs, which the other applicator had already sprayed. She thought they knew what they were doing. Four hours later the family returned to the house to find the carpets wet and a strong odor throughout the house. Since she was told it was harmless, they stayed in the house, thinking, "It's just a pesky odor and will go away." A year after the incident occurred they could still smell the pesticide throughout the house. At the suggestion of the Oregon Department of Agriculture and their finding of "significant level of diazinon" in the house six months after the application occurred, the family moved out of their home. A month later, Mrs. McLaughlin took her baby to the doctor for a check up. The pediatrician was concerned about the child, stating that she was extremely jittery and continue very slow in developing motor skills. When the baby was taken out of the house permanently, she began to improve. They are still making mortgage payments on the house as they have been unable to sell their home due to the contamination.

· Deborah Ryan of Nortonton, Ohio reported that diazinon was applied to her rental property on a windy day in 1990. The application was made by the property janitor to control grubs, chinch bugs, and fleas. Almost immediately after it was applied, she felt nauseous, dizzy, and experienced nose and throat irritation. Her neighbor also was nauseated and her dog became very ill. Ms. Ryan stated that the pesticide was not wetted down as the instructions on the label required. A few hours after the application, the janitor proceeded to blow the excess diazinon off the sidewalks and walkways with a hand-held leaf-blower. During this time, school children were playing nearby. The Pesticide Division of the Ohio Department of Agriculture reported that this incident was a misuse of diazinon.

· William Wilson and his family of Rimrock, Arizona were exposed to Green Light Many Purpose Dust containing diazinon in 1989. It was used to fumigate the mobile home they were renting. Over the following year his entire family suffered a multitude of medical problems ranging in severity for each family member. Exposure occurred through ingestion, inhalation, and absorption. Symptoms included: neurological problems, severe muscle weakness, tendon weakness, headaches, nausea, vomiting, loss of bowel and bladder control, skin sensitivity, blurred vision, thyroid problems, abnormal blood sugar levels, sub normal body temperature, rapid pulse, gastrointestinal problems, and heart problems. Three years after the exposure occurred, Mr. Wilson stated that some of these symptoms still remained.

· Pamis Montagne of North Las Vegas, Nevada was at work, preparing a lesson for her class when a custodian came into her room and sprayed for ants. Some of
the spray mist landed on her skin. She is now completely disabled and no longer able to work.

Environmental Risk Assessment for Diazinon

The introduction to the Environmental Risk Assessment (ERA-Diazinon) states that "the primary environmental concerns associated with the use of diazinon are bird kills, contamination of surface water via runoff, and impacts on aquatic species. These are significant concerns because over 6 million pounds of diazinon is used every year across the United States. The impacts of diazinon use on surface water quality are a particular concern because a significant portion of diazinon is used on lawns in urban and suburban areas where runoff is occurring. Diazinon used in these areas is very prone to runoff into creeks, streams, ponds, and other bodies of water. Available water monitoring data clearly demonstrate that the use of diazinon is resulting in widespread contamination of surface water, and that it is a particularly significant problem in urban settings. Diazinon is also one of the most frequently detected pesticides in air, rain, and fog, suggesting environmental transport into regions beyond normal areas of use." (ERA-Diazinon p. 9)

A summary of the major issues reported in the ERA-Diazinon is as follows:

o Diazinon is one of the most frequently detected pesticides in air, rain and fog;

o Non-agricultural uses of diazinon, including homeowner uses, have significantly affected both surface and groundwater quality;

o Approximately 300 incidents of wildlife mortality, mostly birds, have been documented in the Ecological Fate and Effects Division's Ecological Incidents Information System (EIIS) database from diazinon use, which represents about 10% of all incidents in the EIIS;

o A high acute risk to birds remains on virtually any outdoor use and potentially even some indoor use site, the widespread and frequent mortality is likely to continue if diazinon continues to be used;

o USGS data shows that diazinon is the most commonly found insecticide in surface water nationally;

o Diazinon is very highly toxic to freshwater, estuarine and marine animals;

o Diazinon is very highly toxic to birds by acute oral and dietary routes of exposure, and based on incident reports, appears also to be very highly toxic to birds via dermal and/or inhalation exposure;

o Diazinon is very highly toxic to mammals by inhalation routes of exposure and moderately to highly toxic based on dermal exposure;

o Diazinon is highly toxic to honeybees and other very highly toxic to other beneficial insects;

o The endangered species levels of concern are exceeded for wildlife, aquatic life and terrestrial plants in semi-aquatic areas for all registered uses and application rates of diazinon;

o Many freshwater treatment facilities in 14 states are out of compliance with the Clean Water Act as a result of diazinon residues in effluent.

Each one of these ecological issues requires that EPA take immediate steps to restrict the uses of diazinon. Taken together, this list of adverse ecological impacts meets the definition of an "imminent hazard" under FIFRA and requires that EPA take immediate steps to remove all diazinon from the market.


Our analysis of the preliminary risk assessment for diazinon 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 diazinon represents an imminent hazard to the health of people and the environment and as such EPA must act to remove all uses of diazinon from the market immediately. We look forward to engaging EPA in a meaningful discussion on the issues outlined in these comments.


Gregory S. Kidd
Science and Legal Policy Director