SALT LAKE CITY (ABC4 News) – Salt Lake City recently scrapped a plan to use Air Force tanker planes to spray for mosquitos this summer. Now a group of local doctors wants to end all aerial spraying, claiming it does more harm than good.

As demonstrated in an informational YouTube video, Salt Lake City has used small planes to spray pesticides such as Dibrom over a large area of wetlands northwest of Salt Lake International Airport for years in an attempt to control the insects and the West Nile Virus they can carry.

“Spraying for adult mosquitos using ultra low volume technology or ULV technology utilizes very small amounts of an insecticide over a large area,” Executive Director of the Salt Lake City Mosquito Abatement District Dr. Ary Faraji, PhD explains in the video. “For example, when it comes to our Dibrom applications, we generally put out about .75 ounces per acre of that product. This literally translates to less than an ounce of a liquid solution that’s aerosolized over an area the size of a football field.”

But Founder and President of Utah Physicians for a Healthy Environment Dr. Brian Moench compares it to nuclear testing that contaminated so-called downwinders in the 1950’s and 60’s.

“The evidence is very strong that it is hazardous to public health, not protective,” Dr. Moench said Wednesday. “It is as inappropriate as atmospheric nuclear testing and in fact, there is significant overlap in the health consequences of these two kinds of toxins. Utahns should not tolerate being made Downwinder victims of another type of atmospheric contaminant.”

UPHE claims the pesticides can cause cancer, heart disease, neurologic disorders, birth defects and autism.

“Two-thirds of the risk for autism comes from exposure to the cumulative effects of exposure to numerous toxins, this is well demonstrated in the scientific evidence,” anesthesiologist Dr. Courtney Henley, M.D. said. “And these are the very pesticides being sprayed by the Salt Lake City Mosquito Abatement District.”

Dr. Faraji, released an eight-page response to the UPHE’s claims, stating that all pesticide application is within EPA and CDC guidelines, reading in part “…it is important to ensure that our essential service of mosquito control continues for the protection of public health and enhancement of quality of life for all residents of Salt Lake City. Unfortunately, UPHE’s position does not reflect the current weight of scientific evidence about the risks from treatments for mosquitoes and mosquito-transmitted diseases.”

Dr. Moench stands by his organization’s report.

“We would like all spraying to cease and for that matter we could say the same thing about every other mosquito abatement district in the state,” he said. “This is a practice that spreads biologic poison throughout our environment.”

To read the UPHE report, go :

The SLCMAD response is attached below: 

SLCMAD Response to UPHE Document
SLCMAD has historically utilized the latest science and information available to make informed decisions about mosquito surveillance and control measures utilizing an integrated approach for the protection of public health and enhancement of quality of life. All of these measures are within full compliance of regulatory laws and fully supported by federal agencies such as the Environmental Protection Agency ( and the Centers for Disease Control and Prevention ( A joint statement on mosquito control in the United States by the EPA and CDC may be found here as well: regards to risk and safety of mosquito control pesticides and practices, a direct quote from CDC’s West Nile Virus in the United States: Guidelines for Surveillance, Prevention, and Control states that “Insecticides to control larval and adult mosquitoes are registered specifically for that use by the U.S. Environmental Protection Agency (EPA). Instructions provided on the product labels prescribe the required application and use parameters, and must be carefully followed. Properly applied, these products do not negatively affect human health or the environment. Research has demonstrated that ULV application of mosquito control adulticides did not produce detectable exposure or increases in asthma events in persons living in treated areas (Karpati et al. 2004, Currier et al. 2005, Duprey et al. 2008). The risks from WNV demonstrably exceed the risks from mosquito control practices (Davis and Peterson 2008, Macedo et al. 2010, Peterson et al. 2006)”. That document may be found here: regards to controlling adult mosquitoes, additional information is provided by the EPA ( and also the CDC ( our current experience with COVID-19, demonstrating the fundamental importance of making public-health decisions based on the best science, it is important to ensure that our essential service of mosquito control continues for the protection of public health and enhancement of quality of life for all residents of Salt Lake City. Unfortunately, UPHE’s position does not reflect the current weight of scientific evidence about the risks from treatments for mosquitoes and mosquito-transmitted diseases.

The nine assertions made by UPHE in general terms are as followsPesticides in general, including those used by SLCMAD, represent a widespread risk to human health even at low doses, especially for fetuses and infants.It must first be recognized that all treatment products used for mosquito control by SLCMAD have been fully vetted by the U.S. Environmental Protection Agency (EPA) through their registration process. According to the EPA website, the process of registering a pesticide is a scientific, legal, and administrative procedure through which they examine:the ingredients of the pesticide;the particular site or crop where it is to be used;the amount, frequency, and timing of its use; andstorage and disposal practices.In evaluating a mosquito control product, EPA assesses a wide variety of potential human health and environmental effects associated with its use. Risk assessments are developed that evaluate the potential for harm to humans, wildlife, fish, and plants, including endangered species and non-target organisms, as well as any potential for contamination of surface water or ground water from leaching, runoff, and spray drift. The Food Quality Protection Act of 1996, or FQPA, requires the Environmental Protection Agency to set allowable levels for pesticides in a way that would “ensure that there is a reasonable certainty that no harm will result to infants and children from aggregate exposure to the pesticide chemical residue.” The act stipulated that an additional tenfold margin of safety for pesticide risk assessments shall be applied to account for pre- and postnatal toxicity and for any data gaps regarding pesticide exposure and toxicity, unless there are reliable data to demonstrate that a different margin would be safe for infants and children.EPA is aware of the study referenced by UPHE. This was a single observational study that has many limitations and does not show any causation and uses a different type of pesticide than the one used by SLCMAD from airplanes. There have not been comparable studies showing similar results. The weight of scientific evidence shows mosquito control applications performed according to the EPA labels are safe for all human populations. The author of the referenced study has also stated that: “I would like to add that these results are not sufficient to cause communities to abandon mosquito-prevention programs…” ( In the event future data suggests changes to pesticide labeling and applications, the EPA will require the changes necessary and SLCMAD will follow the label as required by law.Although the EPA and the product label do allow for applications of adult control products directly over urban and suburban habitats, and this practice is common in other parts of the US, SLCMAD has not ever conducted any applications directly over any urban or suburban habitats. Our aerial applications are only conducted over rural habitats located north and west of the SLC International Airport, where wetland habitats abound and where the actual mosquito populations are stemming from.
The VOCs from pesticide spraying is a significant contributor to local air pollution.According to EPA, volatile organic compounds (VOCs) are emitted as gases from certain solids or liquids. Concentrations of many VOCs are consistently higher indoors (up to ten times higher) than outdoors. VOCs are emitted by a wide array of products numbering in the thousands. EPA’s statement that pesticides are only semi volatile organic compounds alone strongly suggests that the adult mosquito control treatments by SLCMAD would NOT be a significant contributor to local air pollution. It must be remembered that SLCMAD will be treating at a dosage rate of less than 1 ounce per acre to reduce the population of biting mosquitoes. These applications are only performed a few times per month during the mosquito season over areas where mosquitoes are most abundant.Additionally, organic chemicals are widely used as ingredients in household products. Paints, varnishes and wax all contain organic solvents, as do many cleansers, disinfectants, cosmetics, degreasers and hobby products. Fuels are made up of organic chemicals. All of these products can release organic compounds while you are using them, and, to some degree, when they are stored. Attempting to single out a component of an Integrated Mosquito Management (IMM) plan designed to protect the public health and improve quality of life to the residents of Salt Lake City and suggest it is a “significant” contributor to local air pollution is inaccurate.
Spraying is not effective in reducing mosquito populations.The latest research continues to show that mosquito control treatments like those performed by SLCMAD are indeed effective for the rapid reduction of mosquitoes.  (Reisen and Brault 2007, Lothrop et al. 2008, Holcomb et al. 2021). SLCMAD routinely monitors mosquito populations utilizing an intricate network of sampling devices (carbon dioxide-baited traps) throughout our jurisdiction. Our before and after control impact determinations has routinely shown an overall reduction of mosquito populations following intervention efforts, further providing empirical evidence that these intervention efforts are indeed effective.
We must not allow a cure worse than the disease. The incidence of severe outcomes from West Nile Virus is so low that preventing those outcomes should not be allowed to eclipse the long list of other health and environmental concerns from pesticide use.This statement ignores the real health effects from those that have been bitten by a mosquito and contracted one of the pathogens they can carry, or those that have tried to enjoy a morning/evening outdoors and have simply been unable to do so due to the sheer number of biting mosquitoes. First, the “small” numbers of individuals that suffer from the more serious forms of mosquito-transmitted pathogens have to learn how to deal with these conditions for the rest of their lives. Many cannot walk or speak clearly and/or suffer severe neurological conditions they do not recover from. Second, suggesting the “cure is worse than the disease” ignores the well over 400,000 thousand people that die a year worldwide from mosquito-transmitted pathogens. And third, 14 people in Utah contracted the neuroinvasive form of WNV in 2019.  According to a Colorado study performed in 2003 costs of WNV-infected people were highest for patients with Acute Flaccid Paralysis (AFP) (median $25,117; range $5,385–$283,381) and encephalitis (median $20,105; range $3,965–$324,167). Long-term costs were highest for patients with AFP (median $22,628; range $624–$439,945) and meningitis (median $10,556; range $0–$260,748). These costs and the associated loss of quality of life simply cannot be ignored.According to the CDC website, adult mosquitoes can spread viruses (like West Nile, St. Louis encephalitis virus, and others) that make you sick. When surveillance activities show that adult mosquito populations are increasing or that they are spreading viruses, professionals may decide to apply an EPA registered mosquito control product to kill adult mosquitoes. Adulticides help reduce the number of adult mosquitoes in an area and reduce the risk that people will get sick. In contrast, the rates at which people could be exposed to pesticides used by SLCMAD are well under the levels the EPA has established to show no harmful effects. To make sure that mosquito control activities are working, SLCMAD monitors and evaluates the effectiveness of their efforts to control adult mosquitoes. For example, if an insecticide did not work as well as expected, professionals may conduct additional studies on the possibility of insecticide resistance or evaluate the equipment used to apply insecticides.According to the Mosquito and Vector Control Association of California, as of 2015 there were 42,876 cases of West Nile virus, including 19,489 cases of the devastating neuroinvasive form and 1,816 fatalities – exactly 1,816 more deaths than those attributable to mosquito control applications. These deaths are documented, not surmised or extrapolated from suspect laboratory studies. I would challenge those criticizing mosquito control operations to visit West Nile virus support groups and observe the very real tragedy of mosquito-borne encephalitis as suffered by survivors of these devastating diseases. Their pain is real – not “associated” or “linked”. To dismiss their distress as an acceptable price for the prohibition of legally registered pesticides strikes me as grossly irresponsible and inhumane.
Spraying does not reduce the incidence of WNV.As an example of the effectiveness of controlling adult mosquitoes to prevent the spread of disease, in Sacramento County, California, a reactive control approach targeting Cx. pipiens and Cx. tarsalis was implemented in 2005 to prevent WNV transmission to humans. Despite early-season larval control and limited truck-based adulticiding efforts, human WNV cases reached outbreak proportions in August 2005 (Carney et al. 2008). In an effort to reduce WNV transmission to humans, the Sacramento-Yolo Mosquito and Vector Control District used aerial adulticide applications of pyrethrin on three consecutive nights in two treatment areas. Before and following the adulticide applications, mosquito abundance was measured using carbon dioxide-baited traps. Results indicated a 75% reduction in the abundance of Cx. pipiens and a 49% reduction in the abundance of Cx. tarsalis in the treated area compared to untreated areas (Elnaiem et al. 2008). In addition, they noted that the WNV infection rate in vector mosquitoes fell from 8.2/1,000 before treatment to 4.3/1,000 after treatment while the infection rate in untreated areas increased from 2.0/1,000 to 8.7/1,000 over the same time period. Occurrence of new human WNV cases also declined in in the treated areas. Before the treatments there was no difference in the incidence of human WNV cases among the treated and untreated areas. After the aerial adulticide applications, the human WNV case incidence in treated areas was significantly lower than in the untreated areas and the odds of human WNV infections were approximately six times higher in the untreated areas compared to the treated areas (Carney et al. 2008). These studies provided evidence that intensive aerial ULV application of pyrethrin in 2005 reduced the abundance of infected WNV vectors and decreased the number of human cases.Suggesting Ae. dorsalis is “only” a nuisance mosquito ignores the intense biting pressure and secondary infections that occur when mosquito populations are over acceptable limits. Outdoor events such as youth soccer, picnics, or even school playground activities would be severely impacted by the emergence and uncontrolled and swelling populations of Ae. dorsalis mosquitoes. And any parent who has watched their child unable to perform on a soccer or baseball field, or later needs to provide topical or oral medication due to unrest, because of the significant biting pressure of mosquitoes appreciates proactive mosquito control measures.  SLCMAD control strategies not only reduce the risk of West Nile virus but also improve the quality of life for all of the residents of Salt Lake City.It should also be recognized that appropriate mosquito control measures will reduce the risk of WNV and other pathogens being transmitted to wild birds and domesticated animals. Several species of birds are very susceptible to WNV (such as crows, magpies and Jays and some raptors), horses suffer debilitating effects from a West Nile virus infection, and many mosquito species are capable of transmitting dog heartworm.
Claims of safety for pesticide spraying use faulty logic and outdated, faulty science.EPA requires the latest science when originally registering a pesticide and ensures an application of a pesticide can be performed safely as long as all label directions are followed.  EPA regulated products are subject to scheduled registration reviews to compare the most recent updates in science on products and their chemistries. In addition to the intensive and complex initial registration process of an insecticide by the EPA through the Federal Insecticide, Fungicide, and Rodenticide Act, all pesticides are also required to go through a re-registration process, as dictated by the Federal Food Quality Protection Act every 15 years. This is to ensure that the latest science and empirical evidence is utilized to make determinations about the safety and environmental impact of all insecticides by leading experts in the field that specialize in this type of work.
There are multiple oversights, inadequacies, omissions, inconsistencies, and errors in the SLCMAD’s EA.The Environmental Assessment conducted by SLCMAD was in regards to a potential partnership with the US Air Force that has now been abandoned. It is important to note that this proposed partnership was intended as a cost savings for the residents of Salt Lake City and was for a single application using another aircraft.
Pesticide spraying has adverse impacts on beneficial insects, bird populations, wildlife, the ecosystem of the Great Salt Lake and beyondEPA’s pesticide registration process ensures there are minimal adverse impacts to non-target organisms. Mosquito control can benefit many bird populations and wildlife that would otherwise be susceptible to intense biting pressure and the pathogens mosquitoes can transmit.
There are Better Ways to Control MosquitoesSLCMAD deploys all of the strategies of an effective Integrated Mosquito Management plan to control the mosquito populations and protect the residents of Salt Lake City from the spread of disease and ensure the comfort of being outdoors. Attempting to compare mosquito control strategies from one area to another ignores the complexities involved with different species, landscapes, geographic and meteorological features that will help or hinder various control strategies. SLCMAD continues to stay educated on the latest mosquito control methods and will continue to adopt new mosquito control methodologies when they are developed.

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