I am concerned as to the safety of what the MRCU (Mosquito Research and Control Unit) are using when they spray to kill mosquitos and its impact on Cayman residents. I assume the liquid adulticides showing on their website are what is being sprayed from the plane. Their website shows two products: Aqua-Reslin (active ingredients permethrin 20%, piperonyl butoxide technical 20%) and Mosquitomist Two (active ingredient chlopyrifos 24.6%).
On further investigation it appears chlorpyrifos is a dangerous substance which is banned in both the EU and the USA (here is a link to the press release). “In December 2014, EPA (Environmental Protection Agency) acknowledged the extensive body of peer-reviewed science correlating chlorpyrifos exposure with brain damage to children, including reduced IQ, delayed development, and loss of working memory. And it found drinking water contamination, particularly harmful to infants, and serious risks to workers from handling chlorpyrifos or entering the fields after spraying.”
Why are they allowed to spray a seriously dangerous substance on the people of Cayman?
Auntie’s answer: A similar question has come up before and in the interest of providing as much information as possible, I suggest you also take a look at that other column (see Worried about spraying of insecticide).
I brought your concerns to the MRCU and an official there described the insecticides they use. To avoid any confusion or mistakes by paraphrasing his explanation, I am quoting him directly: “MRCU utilises two insecticides for aerial control of adult mosquitoes. Our primary insecticide is Aqua-Reslin, which has permethrin as its active ingredient. For control of the Aedes aegypti mosquitoes (the mosquito that transmits Zika, chikungunya, dengue and yellow fever) we cannot use Aqua-Reslin as it is resistant.
“For aerial control of Aedes aegypti we utilise MosquitoMist Two, which has chlorpyrifos as its active ingredient. Both of these products are currently labelled and approved by the US EPA for mosquito control. For larval control we rely on two products, which are applied by air, namely Bti and spinosad. These products are also approved by the EPA and labelled for aerial application.”
These last two insecticides that are used to control larvae come in pellet form.
I also asked the MRCU to address your specific concern about chlorpyrifos and this was their response: “The Pesticide Action Network (which was the source of the information provided by your reader) did petition the EPA requesting that they revoke all tolerances for the pesticide chlorpyrifos under section 408(d) of the Federal Food, Drug, and Cosmetic Act and cancel all chlorpyrifos registrations under the Federal Insecticide, Fungicide and Rodenticide Act.
“The petition was filed in September 2007. This petition was denied by the EPA.”
The MRCU also provided this link to the EPA’s decision, which includes details of the petition.
The MRCU official added, “MosquitoMist II therefore remains an EPA-approved product for mosquito control and its label allows for aerial application.”
For more information, feel free to email the MRCU.