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-34223
We appreciate the opportunity to comment on EPA's preliminary risk assessment for malathion. We would like to begin with a word about process and urge EPA to ensure a more open review process that is open to the public in all respects. It is extremely important that EPA establishes an open process that allows the public open access to the chemical review process. To the extent that this process enables public input into the scientific review process, it is important. However, to the extent that it allows the public into the process after EPA has been lobbied by the regulated community, the process needs to be improved and allow public access at the point that EPA staff completes its initial review.
Stop Closed Door Meetings
EPA should open the meeting process on chemical reviews to the public. No meetings with the chemical industry on risk assessments presented to EPA should be considered confidential unless EPA has determined in advance that the meetings are subject to the confidentiality protections of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), Section 10. Under this process, EPA must make a determination that any and all confidentiality claims are valid. If he were to determined at the front end of the process which information being discussed qualified as confidential, then the public should be excluded from only discussion involving that information.
This is particularly important in the case of malathion because it is our understanding that EPA downgraded its original diagnoses of tumors found in laboratory animals exposed to the widely used insecticide malathion. As a result of a report created by the Pathology Work Group (PWG), a group established by malathion's manufacturer Cheminova, EPA downgraded the severity of the types of tumors that were found in cancer studies. In fact, we have been told that EPA revised its cancer risk assessment, did not involve a senior scientist with longstanding involvement in the review, and based its determination on the industry's analysis. That determination is contained in the preliminary risk assessment that is now the subject of public comments.
The senior EPA toxicologist, Dr. Brian Dementi, in a memo to the Chairman of the Cancer Assessment Review Committee (CARC), concluded, "[U]nder EPA's Guidelines in evaluating the tumorigenic response, the PWG report should be discounted, and the original diagnoses retained."
We urge EPA to revert back to the original diagnoses, subject that to public comment, and answer Dr. Dementi's questions about the adequacy of PWG's and EPA's review.
EPA Fails to Calculate Aggregate Risk Fully
EPA must conduct aggregate short-term risk estimates for food, drinking water and residential pathways because there are potential exposure patterns resulting from a regulatory decision that may cause aggregate short-term risks of this nature.
At page 5, Executive Summary, EPA states, "Aggregate short-term risk estimates for food, drinking water and residential pathways were not conducted because the Aggregate Risk Indices (ARIs) for residential dermal and inhalation exposure alone exceed HED's level of concern for several residential handler scenarios and for several residential postapplication (adult and toddler) scenarios." At page 5, EPA says, "Currently, registered home garden uses of malathion in residential settings result in combined dermal and inhalation exposure that alone exceed HED's level of concern."
If EPA were to design
a regulatory solution that involved continued exposure to malathion during
a phase-out period in addition to allowing existing stocks of malathion
to be used under old labels, exposure to malathion could continue for
a time period that involves public exposure. EPA must calculate this exposure
through an ARI to determine whether exposure during the phase-out period
and during the exhaustion of existing stocks represents an "imminent
hazard." EPA must do this analysis for acute, subchronic and chronic
The nature of organophosphate poisoning demands that EPA not ignore an exposure scenario likely under a regulatory settlement agreement in which exposure to an organophosphate like malathion, whose uses are known to exceed acceptable risk levels, would continue for any period of time. For example, the recently announced decision on chlorpyrifos identifies a similar failure on the part of the agency to calculate real-world exposures during the pendency of a phase-out and existing stock provision.
Similar to malathion, 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." 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.
EPA failure to evaluate the ARI 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. Spp. 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)." In the case of malathion, chlorpyrifos or any other pesticide, EPA cannot satisfy its statutory responsibility without conducting a full ARI for all uses, even when the ARI is exceeded as a result of very few uses.
EPA Must Conduct an Oral Pathway Analysis for Children
EPA indicates that the oral pathway (hand-to-mouth behavior) for children's short-term residential exposure was not included in the short-term aggregate assessment for the public health uses. There is no scientific basis for ignoring this pathway in a public health or other application of a pesticide. Especially in the case of a public health use, where aerial or ground application occurs, exposure will be widespread to soil, lawns, walkways and playgrounds where children play. Children touch banisters, doorknobs, doors, buildings and other surfaces where pesticide residues occur.
EPA Should Adopt Precautionary Principle and Err on the Side of Safety
EPA has adopted throughout the assessment the notion that risk concerns of ARIs close to the unacceptable level can be moderated by risk 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 PPE 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.
EPA should err on the side of public health especially since it acknowledges that, despite the fact that malathion shares a common mechanism of toxicity with other organophosphates, it is not conducting a cumulative assessment which would include malathion's contribution to excessive risk. During this period prior to the adoption of a methodology for cumulative risk assessment, risk concerns of ARIs close to unacceptable levels should err on the side of deleted uses.
Sensitivity to Children
EPA should reconsider its earlier conclusion and consider applying the additional 10-fold margin of safety by evaluating:
1) Sensitivity associated with oral exposure to neonates.
2) The NOAEL in developmental neurotoxicity, based upon structural alternatives in brain development as the toxicity endpoint of concern.
3) Whether inhibition of cholinesterase may not be essential for adverse effects on brain development
Cancer Analysis Should Be Revisited
EPA should adopt the position that malathion is a likely carcinogen based Dr. Brian Dementi's evaluation.
Summaries of memos from Dr. Dementi follow:
Attachment 1 - 11/26/1997
Note - Dr. Dementi's concern that the CARC is associating tumor response with toxicity rather than the carcinogenicity of malathion. He states that he is "not aware that anyone demonstrated at the CARC, either on the rationale of cholinesterase inhibition or any other parameter of toxicity, that the tumorigenic findings in the mouse study were "solely the result of excessive toxicity rather than carcinogenicity of the tested agent per se."" This is the standard required by EPA for Carcinogen Risk Assessment. (see page 2) The EPA understates the rarity of nasal tumors in the MRID study. (see page 3) He also points out that "since there was not NOEL in the inhalation study, exposure to low and possibly unknown concentrations by this route are problematic in terms of affirming public safety via the inhalation route of exposure." (see page 4)
Attachment 3 - 4/9/1998
This is an early memo with his concerns after a HIAR meeting (malathion hazard identification committee). Dr. Dementi validated his concerns with malathion liver tumor responses across all dose levels, including the 100 ppm group, with NIH. (see page 3)
Attachment 5 - 5/29/1998
Dr. Dementi's closing statement should be noted. "The whole issue is of more than academic interest, for it is both surprising and of considerable concern where protection of the public health is concerned should malathion be a carcinogen at does as low as 100 ppm. By this I mean the stakes are too high for people to say, we don't believe this could be so, in spite of the evidence, and then walk away from it."
Attachment 8 - 4/1/1999
Dr. Dementi's concern that EPA removed the FQPA 10X safety factor without merit.
Attachment 9 - 4/27/1999
Dr. Dementi confers with an expert pathologist with NIH National Toxicology Program on leukemia responses and carcinogenicity and sends another memo to the CARC Chairperson on a possible association of malathion with leukemia.
Attachment 15 - 9/21/1999
This is another memo to William Burnam, with EPA's Health Effects Division,HED. Mr. Burnam is the Chairperson of the EPA Cancer Assessment Review Committee,CARC. Dr. Dementi expresses concern again for the tumorigenic responses at low dose levels and calls again for external peer review. He would like to see credible peer review from academia, not some industry chosen panel, in an effort to avoid any biased conclusion. The CARC authored the section in EPA's malathion documents titled "Evaluation of the Carcinogenic Potential of Malathion" and appears to have given more credence to the last minute Cheminova convened Pathology Working Group, PWG, assessment of the test data than any of Dr. Dementi's assessments over the last three years. The finding of the CARC in their final report on malathion was,"suggestive evidence of carcinogenicity but not sufficient to assess human carcinogenic potential."
Attachment 16 - 10/6/1999
Dr. Dementi does not agree with the final EPA assessment on malathion that, "The toxicology data base is complete and there are no data gaps."
Attachment 26 - 4/27/2000
This is a memo from Marion Copley, Doctor of Veterinary Medicine, with EPA's HED and member of the CARC for malathion. EPA's William Burnam, Chairperson of CARC, asked her to prepare responses to Dr. Dementi on items he considered "factually incorrect or unclear" in the CARC report. Dr. Copley responded to 52 items. Dr. Dementi's concerns are listed first, followed by Dr. Copley's response. Dr. Dementi's comment was, "At necropsy, liver "masses" were seen at all dose levels, but not in the control." Dr. Copley responds with a quite different conclusion, possibly allowing for an interpretation that there were incidences of liver masses in the control group." The following will be added to the CARC report, "At necropsy, liver "masses" were increased over controls in all male dose groups and at 16,000 ppm in females."
Attachment 29 - 4/27/2000
Cheminova did not agree with the results of EPA's assessment of malathion's carcinogenicity and convened the Pathology Working Group to re-review their liver tumors data submittals resulting in a downgrading of malathion's potential to cause cancer.
On page 6, Dr. Dementi receives the opinion of Dr. Maronpot of the National Toxicology Program on the conduct of PWG. He advises that Dr. Dementi or another EPA scientist participate in the peer review process. This would be necessary to evaluate the performance of the PWG. Dr. Dementi was never notified of the PWG until the day of the review, making it impossible for Dr. Dementi to attend.
On page 7, Dr. Dementi questions the ability of the PWG pathologists to evaluate 620 slides as quickly as they did.
On page 7, the PWG did not rank the severity of the hepatocellular alteration diagnoses. This is important because it makes it difficult for the EPA to distinguish and estimate the final incidences of those that might be of greater concern. It is possible that the moderate to large hepatocellular alterations could be qualitatively the same as adenomas, but without the rank of severity, such conclusions would be lost.
On page 7, the PWG focused narrowly on neoplasms. However, Dr. Dementi believes that they should also be looking at preneoplastic lesions. The PWG only reported hepatocellular lesions with moderate degrees of severity.
On page 7, Dr. Dementi points out that the PR notice calls for a diagnosis or re-diagnosis of histopathology findings, NOT for an interpretation of carcinogenicity, this is what the PWG did, and it was not their position.
On page 8, while the PWG reported that the lowest effect level for hepatocellular neoplasms was 12,000 ppm for the female rats, Dr. Dementi believes that the PWG's report does not permit the determination of a lowest effect level.
On page 8, the progression of lesions, as referred to in Eustis et al (1990) as the "natural history of neoplasia" must be included in the assessment of tumorgenicity under EPA's guidelines
On page 10, Dr. Dementi questions the difference in the PWG's diagnosis of hepatocellular alterations, adenomas, and carcinomas. Unless there was a change in criteria, such a disparity would seem unreasonable.
On page 13, Dr. Dementi concludes, "Because the PWG report does not provide instances of hepatocellular alterations to be used as 'key events' the PWG report should be discounted and the original diagnoses be retained." He is also concerned with the "remarkable changes of diagnoses of tumors in the current PWG..."
EPA Fails to Calculate Real World Exposure in Risk Assessment
EPA does not adequately evaluate real world exposures to malathion, including mosquito adulticide characteristics and application techniques, exposure pathways, environmental types and representative areas, and the public health risk assessment. The following comments address these shortcomings.
Adulticide Characteristics and Application Techniques
EPA's risk assessment of malathion fails to include an analysis of the efficacy of controlling adult mosquitoes through the spraying of malathion, given that EPA is evaluating a public health use. That analysis should include the life history and behavior of all of the vector species of mosquito, and a calculation of the fraction of adulticide that is actually hitting and killing its intended target. The technique used to apply this adulticide has to be carefully analyzed. The effectiveness of the various spray options - backpack, truck and aerial - must be determined, and the drift associated with each option must be calculated. The EPA must consider the effects of spraying malathion near, or over, water, and take into account factors that might cause non-target impacts, such as drift, volatilization, and accidental releases. It also needs to consider the difference in breakdown rate, or half-life, of the adulticide that enters the subway systems, like that of New York City versus the pesticide that is exposed to sunlight.
The EPA fails to factor in all potential pathways of malathion exposure scenarios: outdoor fruit stands, outdoor food vendors, and vegetable gardens. The EPA must include a determination of the amount of pesticides absorbed and trapped by air conditioner filters and drifted into buildings through open and closed windows.
Environment Types and Representative Areas
The EPA fails to consider all people that are parts of communities being exposed to malathion. The EPA must consider the homeless population around the country. If/when spraying of malathion occurs in their city or town, these people will not necessarily have shelter to avoid the exposure. In addition, the prison population in area must also be taken into consideration. The EPA fails to identify the environments where there is a strong likelihood that the malathion will become concentrated, including golf course ponds, and other bodies of water without outlets.
Air Drift/Deposition Modeling
The EPA must consider sources of wind and temperature data, in areas of high-rise buildings and in open areas. Pesticide drift must be an important component in identifying the risks associated with the use of malathion. Drift in agriculture areas differ to urban situations. For example, updrafts and thermals associated with the urban setting must be factored into the risk assessment for malathion.
Public Health Risk Assessment
The EPA fails to analyze the quality of the information that will be provided to the health care community and the general public about the impact of pesticide exposure. The risk assessment must factor in all types of people, including men, women, children, people suffering from Multiple Chemical Sensitivity, the elderly, and those with weakened immune and nervous systems.
The EPA must place equal emphasis on the sub-chronic and chronic effects and acute effects of malathion exposure. The EPA fails to consider the background level of chemicals and pesticides in communities across the country, the existing body burden and potential risks caused by the aggregate effects of these chemicals.
The EPA fails to answer the following questions that must be considered in the risk assessment for malathion:
o How are the pesticides
o Who is responsible for storage, transportation and disposal?
o Where and how will waste be disposed of?
o How are applicators and disposal companies be evaluated and policed?
o What emergency plans have been created to address an accident associated with the transport, use, storage and disposal of the chemicals used and what are the risks associated with accidents?
Without addressing the mentioned points, the EPA continues to ignore the use of malathion in "real world" situations. The EPA must provide for the greatest protection of the public health, an approach that reflects the very real risks associated with exposure to pesticides.
Thank you for your attention to these issues. We look forward to providing you with additional information throughout the process of review.